Game mechanics

Path of Exile can be intimidating for new players due to the fact that a certain level of understanding of game mechanics is demanded of players who wish to survive. In order to help facilitate planning and execution, this page contains information on the most important mechanics to understand and links to pages which explain specific mechanics in greater detail. It is intended to serve both as a guide to new players and as a primary reference for existing ones.

=Leagues=

Before beginning path of exile players are given options for different leagues to choose from. Players can only interact with other players in the same league as them. Most items owned by players are restricted to the league they are found in, with some exceptions below.

There are 4 permanent leagues called standard leagues.
 * Standard - The game with no modifiers.
 * Standard hardcore - Modified so characters can not die or their character and characters inventory move to standard. Items stored in stash will not move to standard on death.
 * Solo self found standard - Modified so that players are alone. No trading or fighting with friends.
 * Solo self found standard hardcore - Hardcore and Solo Self found modifiers together. Characters that die go to solo self found standard.

Aside from the parent leagues, Path of Exile releases temporary challenge leagues of the parent leagues that include new features to the game. These are like ladder resets, in that everybody joins the league with no characters and an empty stash. When temporary leagues end all characters and inventories and the stash will all move to standard.

Temporary leagues have the same options as standard has above giving a total of 4 leagues. The temporary leagues with no modifiers tend to be the most popular leagues. Higher player population makes finding a party or rare items for trade easier.

=Classes and stats=

Classes
The main difference between the classes is their starting location on the passive skill tree and their Ascendancy class. Classes also start with different amounts of attributes and have different quest rewards.

Ascendancy Classes
Each base class can choose from one of three Ascendancy classes (except for the Scion, who has only one) after completing the Lord's Labyrinth. Ascendancy classes offer powerful, specialized passive skills. You gain 2 Ascendancy skill points for each difficulty of the Labyrinth you complete, with 4 difficulties in all.

What is gained per level?
All classes begin with the same base stats, and gain the same amount life, mana and evasion per level. Classes start with different accuracy stats but gain the same amount per level. The values all classes gain per level are:

Attributes
Attributes are required to equip gear and skill gems. The three attributes also grant some passive bonuses.

Life and mana regeneration
All classes have a base mana regeneration rate of % of their maximum mana per minute. For example, a character with 100 maximum mana will regenerate mana per minute, or  mana per second. "Increased Mana regeneration rate" modifiers modify the base rate. For example, 20% Increased Mana regeneration rate would result in * 1.2 = % per minute.

Characters do not begin with any life regeneration, but it is available from gear and passive skills.

Leech
Leech recovers over time an amount of life, Mana or Energy Shield relative to the damage inflicted on an enemy. Vaal Pact and Ghost Reaver doubles the amount of Life and Energy Shield leeched, respectively.

=Private Stash=

Your private stash allows you to store items and transfer them between characters. Stashes are shared between all your characters within a league - all of your Standard characters access one stash, while all of your Hardcore characters access a different stash. Items cannot be moved between leagues except by death to a character (From Hardcore or Challenge League Hardcore to Standard). Each account is initially limited to 4 stash tabs, but more can be bought through microtransactions.

=Chat Channels=

There are two types of chat channels: Trade and Global Chat. These channels are League-specific. If you enter global chat in Domination League, then you will only be talking with people in that league only. Typing /global ## or /trade ## will put you into that number channel, provided it is not full.

Messages can be directed to different channels. Messages starting with You can leave global or trade chat by unchecking the "Join Global Chat" or "Join Trade Chat" options on the chat window.
 * # are sent to the global chat channel you are in.
 * $ are sent to the trade channel you are in.
 * & are sent to your guild chat if you are in a guild.

=Skill Gems=

Skill gems are the manner in which player characters are able to use and augment skills. Gems are placed in sockets by left-clicking it in the inventory to pick it up and then left-clicking it over the intended socket. Right clicking will remove the gem. Gems are either active skills or supports, and skills come in several types whereof the two most common are Attacks and Spells.

Active skill gems
Active skill gems creates the skill. They can come in various forms, such as attacking or casting a spell, summoning a minion or totem, throwing a trap or placing a mine, activating an aura or buff effect, and so on.

Support skill gems
Support gems augments the active skills, for example by increasing its power or adding more projectiles. The support gem needs to be linked to the active gem to be active and the support needs to be able to support it. Reading the gem's tags is helpful in determining which support gems can support which skills. Common sense is also helpful - skills that don't do damage, such as, won't benefit from nor would it add damage to an Aura. Note that skill properties may change depending on weapon -, for example, is tagged with both Bow and Melee because it can be used with either, but won't work when Elemental Hit is used with a sword.

Gem experience gain

 * Gems are not affected by the experience penalty when facing enemies below your level.
 * Equipped gems get experience equal to 10% of the experience you earn.
 * The number of gems you have equipped has no effect on the rate of XP gain. So having fewer gems equipped does not cause them to gain XP faster than if you had many gems equipped.
 * Gems do not lose experience when you die.
 * Gems bought from Vendors gain experience and increase in levels when the player levels up. Gems dropped from monsters and containers are level 1, higher level gems can also drop from other sources, such as a Strongbox.

=Damage Scaling and Effects= See also Damage Types. Understanding how damage scales is very important in Path of Exile. There are 5 main types of damage, which are Physical, Fire, Cold, Lightning, and Chaos. Fire, Cold, and Lightning are collectively known as Elemental Damage. Damage reduction from armour only affects physical damage.

Hit & damage calculation order of effects
There are a number of steps involved in deciding whether an attack hits or not and how much damage is done. From the accuracy of the monster to the evasion, armour, dodge and block chance of the character.

Chaos Damage
Chaos damage bypasses energy shield. Chaos damage is not considered to be "elemental damage".

Elemental Damage
Elemental Damage refers to fire damage, lightning damage and cold damage collectively. Passives or items which refer to elemental damage or elemental resistance will affect all 3 of these Damage Types or Resistances.

Fire damage If you land a critical strike with an attack or spell that deals fire damage, the enemy is Ignited and begins Burning. Ignite causes damage over time equal to a portion of the damage that applied the Ignite. Some enemies such as Humanoids, Monkeys and Sea Witches will flee while Burning. Multiple instances of ignite can be applied at the same time, however the damage from them does not stack. Only the highest-damage burning effect from a single source that is on a creature at any one time will deal damage. However, burning damage from multiple sources can add on to each other. (See Burning)

Cold damage Hitting an enemy with cold damage can cause the enemy to be Chilled. Critical hits with cold damage can also cause the target to be Frozen. Chilled enemies move, attack, and cast slower, while frozen creatures cannot perform any action except drink flasks. Frozen creatures can still block, dodge and evade while frozen. Frozen enemies shatter on death, destroying their corpse.

Lightning damage If you land a critical strike with an attack or spell that deals lightning damage, the enemy becomes Shocked. Shocked monsters or players take increased damage while shocked. The damage multiplier itself applies multiplicatively with your final damage, since it increases the damage the enemy takes, rather than the damage you deal.

Status ailments
Ignite, Chill, Frozen, and Shocked are collectively known as Status Ailments. They can for example freeze or burn the monster for a duration.

Dual wielding
Dual wielding grants a bonus to attack speed, and block chance. The attack speed bonus is applied multiplicatively with other attack speed modifiers. The default attack and most other skills will alternate between each weapon, striking with each hand in turn. ,, , and attack with both weapons at once, while most other skills will alternate between each weapon. For skills that are weapon-restricted, both weapons must be compatible in order to use the skill.

Stuns
Whenever a player or monster takes damage of any type, there is a chance they will be stunned. A stun interrupts whatever that creature was doing while a brief animation is played. The duration of stuns can be altered by increased block and stun recovery, increased stun duration, and similar modifiers.

Accuracy
Accuracy is compared to the enemy evasion rating when determining if an attack hits or misses. Spells and secondary damage will always hit.

Critical Strikes
Whenever you use a skill or attack, you have a chance to deal a critical hit. Critical strikes are rolled on a per-action basis, not per-monster. If you roll a critical strike when using a skill, you will deal critical damage to all enemies hit by the skill.

Critical strikes do more damage than normal, based on your Critical Strike Damage Multiplier. All characters have a base Critical Strike multiplier. This multiplier can be increased with various skills and modifiers on items, for example: or the modifier.

Critical Strike Chance and Critical Strike Damage Multiplier are calculated separately for each spell and weapon attack. All weapons and damage-dealing spells have a base Critical Strike chance listed on them. This only affects your chance to critical for attacks made with that weapon or spell. For instance the base critical strike chance on a wand does not affect your chance to critical with a spell.

However, global modifiers that appear on weapons (or anywhere else) can and will affect your chance to crit with any attack or skill. They will stack additively with other mods of the same type, such as those found in the passive skill tree.

Local Critical Strike Chance modifiers (ones on the weapon itself) affect the base critical strike chance of the weapon - the weapon's modified crit chance will be shown in blue on the weapon's description. This makes Critical Strike Chance modifiers that appear on weapons more valuable than other sources on a point-for-point basis.

Non-spell critical strikes can be evaded. See the evasion section above for details.

Combining damage properties
Path of Exile uses wording that is as literal as possible according to the classifications listed on this page so that consistent damage calculations can take place. For example, take. It is a projectile attack that uses a melee weapon. This means that, for example, a passive node that grants will boost Spectral Throw's physical damage when used with a two-handed melee weapon such as a staff, but a node that grants  will not boost Spectral Throw's physical damage, because Spectral Throw is a projectile attack, not a melee attack. This approach to properties is true of all mechanics in the game, but is most often a source of confusion for damage stacking.

Damage conversion
Some skills and gear can convert one type of damage to another, resulting in a complex damage calculation. Damage conversion stacks additively, and is scaled down to fit 100% if total conversion exceeds 100%. Bonuses from different damages types are applied to the final product as though they were the same type - for example, if you had 100% cold to fire conversion 100 base cold damage 50% increased cold damage 50% increased fire damage Then you would have 50%+50% increased fire damage (see the following section), or 100% increased fire damage. This means your final damage is 200 fire damage.

=Modifier stacking=

In general, integer modifiers are applied before percentages. Percentage modifiers using the words "% increased" or "% reduced" stack additively with one another, while "% more" and "% less" modifiers stack multiplicatively.

When dealing with weapons, some modifiers that are listed on the weapon itself are applied first, before mods from other pieces of equipment, skills, and so on. This includes anything affecting physical damage, such as increased physical damage, added physical damage, quality etc., and also attack speed, critical strike chance, and accuracy. It does not include elemental damage mods. These can be called local modifiers - any modifier marked as "global," such as %increased Global Critical Strike Modifier, is not applied to the weapon first.

Similarly, when dealing with armour, evasion, and energy shield on armour, any modifiers affecting those stats that are listed on the piece of armour are applied first. This includes quality and any other mods directly affecting armour, evasion, or energy shield amount. It does not include mods affecting the energy shield recharge delay or regeneration rate, only the amount of energy shield.

Imagine I have 100 life, and two passive skills that each increase total life by 15%. The total bonus will be 30%, resulting in 130 life. Now imagine I am wearing boots that give +40 life, and have a passive skill that grants +20 life. The integer bonuses are applied first, giving me 160 life, then the percentage bonuses are applied to that subtotal, for a final total of 208 life.

For example, let's look at a Samite Helmet with +69 armour, 92% increased armour, and 20% quality. This Horned Casque has a base armour rating of 240. Then the +69 is added to get 309 armour. Then the 92% bonus from the item and the 20% bonus from quality are added together to give a 112% armour increase, for a total of 655 armour.

Another example calculation If you had a sword whose unmodified damage is 10-20, with the following modifiers:

50% increased physical damage on the weapon; 20% quality on the weapon; 5-10 added physical damage on the weapon; passive skills granting 30% increased sword damage; a skill that does 40% increased damage and 30% less damage;

the calculation would would look like this:

Base damage: 10-20 Stage 1, on-weapon modifiers: (10-20 + 5-10) x (1 + 0.5 + 0.2) = 25.5-51 Stage 2, all other modifiers: (25.5-51) x (1 + 0.3 + 0.4) x 0.7 = 30-61

=Defensive mechanics=

Movement Speed
The base movement speed bonus of your character is 0%, or normal speed. If your movement speed bonus is at 0%, then it will not be shown on the "Defense" tab of the character screen. However, if it is anything else, such as -2%, it will be shown in the "Defense" tab.

Shields and body armours have hidden intrinsic movement speed penalties. Body armour based on armour or armour and energy shield cause 5% reduced movement speed. All other body armours cause 3% reduced movement speed. Shields cause 3% reduced movement speed. These are the nonmagical components; unique body armours such as can modify movement speed further.

Armour
Armour only reduces physical damage taken when hit. Elemental damage and damage-over-time are not affected. How much damage that is reduced depends on the defender's total amount of armour rating and the attacker's attack damage.

In a practical sense, this means that the higher the damage of a single hit, the more armour penetration it has. This also means that higher armour is much more effective against multiple smaller hits rather than one big hit. The fact that damage reduction scales with the amount of damage means it is difficult to know exactly how much damage is being reduced. The maximum physical damage reduction is %.

Evasion
Evasion rating increases chance to evade an attack. Evading an attack prevents all damage and other harmful effects from the attack. Only attacks and attack skills can be evaded. Spells cannot be evaded.

Evasion also gives a chance to avoid critical strikes. If an incoming critical strike succeeds its hit roll, a second hit roll is performed to determine if the critical is evaded or not. This second roll is the same as the regular hit roll above (accuracy vs evasion). If this roll succeeds, a critical strike is scored. If it fails, the attack still hits, but only for regular damage. Critical strikes from spells cannot be evaded.

The way evasion is calculated prevents streaky results. Path of Exile uses an "entropy" system to ensure that hit results are evenly spaced out - for example, if an enemy has 33% chance to hit you, then after you are hit, you are guaranteed to evade the next two attacks from that enemy, and guaranteed to be hit on the next (third) hit. Detailed explanations can be found on the evasion page.

Energy Shield
Energy Shield acts as an additional hit point pool on top of life. If you have any Energy Shield remaining when you take damage, the damage is subtracted from the Energy Shield first. Damage is only applied to life once all Energy Shield is depleted. The exception to this is Chaos Damage, which ignores Energy Shield under normal circumstances.

Energy Shield will recharge if you do not take any damage for a certain period of time. This time can be reduced with modifiers from passive skills. The Recharge rate can be increased with modifiers on passives, jewels, and equipment.

As long as you have greater than 0 Energy Shield, you have a 50% chance to avoid stun.

Blocking
Blocking an attack prevents all damage and other harmful effects from the attack. Usually, only attacks and attack skills can be blocked, but there are some passive skills and unique items that allow you to block spells.

The chance to block attacks and spells are both capped at %.

When an attack is blocked, the game first calculates if the attack would have caused a stun were it not blocked. If it would have caused a stun, the blocking animation is played, stunning you briefly. If it would not have caused a stun, then you get a "free" block with no animation. Faster Block and Stun Recovery and Increased Block Recovery modifiers reduce the length of the blocking animation.

Resistances
Fire, Cold, Lightning, and Chaos damage each has its own resistance value (e.g. "Fire resistance") which can be viewed in the character sheet. Resistances reduce damage taken (or increase damage if they are negative), and are capped at:

After beating the boss of Act 5, a character's resistances are reduced by 30%. After beating the boss of Act 10, a character's resistances are reduced by 30% percent, bringing the total to 60%. A character would need 135% resistances to cap out at 75%

=Adventuring=

Currency
Instead of gold or other forms of money, Path of Exile uses what are known as "currency items". Currency items are displayed with light tan text color in their item name. In addition to their use as units of trade, each type of currency item can alternatively be consumed for a specific gameplay effect, such as in crafting or gambling a piece of equipment.

When you buy items from NPC vendors, those items will cost some amount of currency (usually low-tier currency). When you trade with players, be prepared to barter or haggle unless a player has listed a "buyout", a set price for the item. Exchange rates between currency items are generally set by the players, as currency items can only be traded up to the next level of currency at a vendor and not traded down.

If an item has reached the max number of sockets, it is impossible to use a Jeweller's Orb on it. If a 5-socketed item has reached 5 links or a 6-socketed item has reached 6 links, it is impossible to use an Orb of Fusing on the item.

Here is some basic information on currency tiers which has been adapted from Noperative's guide. The tiers are player-defined and some players may not agree on them.

God-Tier: These are the rarest and most expensive items in the game. Having just one means you're richer than some people who have been playing this game since it was released.

,, High-Tier: These are usually items that are valuable in the end-game and are very rare. They are high-value currency items that most players would prefer to save rather than expend. They can be traded for big-ticket items or used on the highest level end-game maps.

,, , , , Trade-Tier: These are items that have high utility and moderate rarity. They are the first items that you can reasonably trade items for and are best saved for the endgame. Some orbs, for example the Chromatic Orb and Orb of Chance, are on the border between trade-tier and low-tier. Whether they fit into one or the other depends on player opinion, patch results and league.

,, , , , , , , , , , , Low-Tier: These are rarely used in trading. Most are bought by the hundreds or thousands because of higher abundance than utility. Most people will keep a few stacks of these to use on items they own rather than go through the effort of selling them. Some items, such as the Glassblower's Bauble and Blessed Orb, are much rarer than other orbs but are not used in bulk and so they are not as easily accepted as currency.

There is a general copper-silver-gold-like progression that can be memorized to help buy out or evaluate items from other players. The following orbs can be stored and used as currency in order to circumnavigate the process of bartering. 4 Orbs of Transmutation -> 1 Orb of Augmentation (NPC) 4 Orbs of Augmentation -> 1 Orb of Alteration (NPC) 8 Orbs of Alteration <-> 1 Orb of Fusing or 1 Orb of Alchemy (between players; Alteration -> Fusing is NPC and players widely consider Fusing and Alchemy to be 1:1) 2 Orbs of Fusing or Orbs of Alchemy <-> 1 Chaos Orb (Players) Items on websites like poe.xyz.is are widely listed with buyouts in terms of chaos orbs, orbs of fusing, and exalted orbs.

Other exchange rates vary over time and differ from player to player. The progression above is not considered a law when trading with players.

Attribute requirements
Most gear has attribute requirements that must be met in order to equip it. These requirements come from the base item type and are unaffected by magical modifiers, quality, or number of sockets. If a gem has attribute requirements a character does not meet and the gem is socketed in an item then that character will be unable to use that item.

Level requirements
Most items have a level requirement that must be met in order to equip them. There are two factors that affect level requirements:
 * The level of the base item type. This is the level that the item starts appearing (and is separate from the itemlevel that affects which magical modifiers can spawn on it). See the item data link above for a list with all item levels. Some of the very low-level base items do not come with a level requirement.
 * The level of the magical modifiers. The level requirement for magical modifiers is equal to 80% of the level of the highest-level magical modifier on the item.
 * The highest level requirement of the two listed above is the one that appears on the item.

Drop rates
Drop tables are uniform across monsters of the same monster level. In other words, the pool of items that can potentially drop and the chance for a particular item to drop are not determined by the type of monster.

Level difference currency penalty
There is a penalty to the chance of currency items (scrolls, orbs, etc.) dropping in areas with a monster level more than two levels lower than a character's level. Currency item Drops are not increased or decreased in this way when fighting in areas above your level. For the purposes of this penalty, your level is never considered to be higher than 68. Therefore a level 75 character receives no penalty in a level 66 area.

There are two modifiers that affect drop rates in the game, increased item rarity, and increased item quantity. There are three potential sources of these modifiers: - the player (skills, passives, gear etc.) - monsters (such as bosses and champions) - Party bonuses Modifiers from the player stack additively with each other, and are subject to diminishing returns. Modifiers from the party bonus and monsters stack additively with each other, and are not subject to diminishing returns. The total player bonus stacks multiplicatively with the total party & monster bonus.

Item Rarity
Increased Item Rarity % modifiers (or IIR) increase the chances of an item being magic, rare, or unique. IIR increases with diminishing returns but they are only significant at very high IIR values. IIR has no effect on the number or type of currency items, scrolls, or gems that drop. When in a party, only the modifier from the character who lands the killing blow on an enemy is counted. If one of a character's minions lands the killing blow then the minion's IIR is added to the character's IIR and that sum is used.

Magic, rare, and unique monsters have an IIR modifier for drops.

Item Quantity
Increased Item Quantity (or IIQ) increases the average number of items that drop from monsters and chests. It does not affect the type, quality, or rarity of item dropped, only the chance that something will drop. There is no cap on the usefulness of this modifier, as monsters can drop more than one item at a time. The base chance for an item to drop from a normal monster is 16%. This varies between monster types, and special monsters have higher drop chances.

When in a party, each player in the party after the first gives a +10% item quantity and +40% item rarity modifier on drops.

IIQ & IIR modifiers from support gems currently do not work with kills made by damage over time effects, such as the poison from poison arrow. Modifiers from your gear will affect those kills however.

Quality
All weapons, armour, flasks, gems, and maps can randomly receive between +1% and +20% quality when dropped from a monster or container. This value can be increased by Blacksmith's Whetstones, Armourer's Scraps, Glassblower's Baubles, Gemcutter's Prisms, and Cartographer's Chisels, but is capped at 20%.

The effect of quality depends on the item: On weapons, increased physical damage On armour, increased Armour rating, Evasion, and Energy Shield On life and mana flasks, increased life and mana recovery On utility flasks, increased duration On gems, the bonus is specific to each gem. Check the individual gem page for specifics On maps, increases the item quantity bonus from monsters in the map area

There are a limited number of ways to increase quality beyond +20%, such as using a on an item or with Hillock's crafting bench in an Immortal Syndicate safehouse.

Modifiers on items
Modifiers are split up in to two main groups, prefixes and suffixes. A magic item can have only one prefix and one suffix, never two prefixes or two suffixes. Rare items can have up to six modifiers, it is unknown if there is a limit on how many of these can be prefixes/suffixes. A randomly generated rare item (from a drop or Orb of Alchemy) receives between four and six modifiers randomly, with the following odds: 1/12 chance of 6 mods 4/12 chance of 5 mods 7/12 chance of 4 mods

All modifiers have a level associated with them, and will only appear on items whose item level is greater than or equal to the modifier's level.

Lists of available magical modifiers are available in the item data section.

The Culling Strike modifier (found on some unique items and ) causes monsters to die if you strike them down to 10% or less life.

Sockets
There are four types of sockets:
 * Strength (red)
 * Dexterity (green)
 * Intelligence (blue)
 * Neutral (white), appearing on or corrupted items. The Locus of Corruption has a chance to turn all sockets white.  s can create rare items with up to 3 white sockets. The rare items can then be scoured and keep their white sockets. Missions from The Immortal Syndicate can make up to 3 random colors white on an item.

Sockets appear randomly on most equipment. Higher level items can appear with more sockets than lower level items of the same type. The maximum amount of sockets that can appear on an item also varies by the type of item:
 * Two handed weapons and body armour can have up to 6 sockets
 * Wands, shields, and one handed weapons can have a maximum of 3 sockets
 * Unset Rings and Black Maw Talismans can have a maximum of 1 socket. is an exception to the normal socket limit on rings.
 * Everything else can have a maximum of 4 sockets

Items are more likely to receive sockets that match their attribute requirements. So an item requiring only dexterity is more likely to have green sockets than red or blue sockets. You can only put a blue (intelligence) gem in a blue socket, red gem in a red socket, etc. Sockets can be linked. The links are shown as gold bars between the sockets. Support gems affect any skill gems in sockets that they are linked to.

For example: This sword has 1 strength socket, 1 intelligence socket, and 2 dexterity sockets. Every socket is linked to every other socket. In this sword you could put:
 * 4 skill gems. You would get access to 4 active skills.
 * 3 skill gems and one support gem. You would get access to 3 active skills, and all three would be improved by the support gem.
 * 2 skill gems, 2 support gems. You get 2 active skills, both are improved by both support gems
 * 1 skill gem, 3 support gems. You get 1 active skill that is boosted by all 3 support gems.

So let's say you put in: You would get a cleave skill that does extra cold damage, and raise zombie skill with zombies that do extra cold damage. You would not get zombies that have cleave, or raise a zombie every time you use cleave.
 * skill gem,
 * skill gem, and
 * support gem.

If two of the same support gem are linked to the same skill within the same socket group, they do not stack. Only the highest-level gem gives a bonus.

Additionally, two skill gems of the same type can be used in separate socket groups, resulting in more than one usable version of that skill. Skill Gems are only affected by support gems in the same socket group. For example, imagine a piece of armour with 5 sockets. The first two sockets are linked in one group, and the remaining three sockets are linked in a separate group. If you put Cleave and Faster Attacks in the first group, and Cleave, Added Fire Damage, and Added Cold Damage in the second group, you would have two different versions of cleave available - one cleave skill that attacks faster, and another cleave that does bonus fire and cold damage. Small letters appear over the skill icons for each support gem you have attached to that skill. This allows you to differentiate between the different versions if you have more than one of the same skill gem equipped.

Item level
Each item has a level associated with it that is equal to the monster level of the area it dropped in. The monster level is shown on the map overlay (TAB key). Magic monsters (blue name) have +1 to their level, and will yield items with an item level one level higher than other monsters in the same area. Rare (yellow name) and unique (brown name) monsters have +2 to their level, and will yield items with an itemlevel two levels higher than other monsters in the same area. You can check an item's level by picking it up on the cursor and typing /itemlevel in the chat box. This item level determines which modifiers it can receive, and how many sockets it can receive.

Charges
Some skills grant Endurance (strength), Frenzy (dexterity), or Power (intelligence) charges. Each charge lasts a short duration before it disappears. The base duration is 10 seconds. Gaining a charge resets the duration of all accumulated charges.

By default characters can have a maximum number of 3 active charges of each type at one time. This maximum can be increased by certain passive skills and unique items.

Parties
The maximum party size is 6 players.

Effect on monsters
Monsters have increased life for each member inside a party.

The original life amount is used for the purposes of determining the length of stuns and status ailments from elemental damage - this means monsters will not be harder to stun/ignite/etc. when fighting in a party.

Effect on loot
Each player in a party after the first gives a increased item quantity modifier and increased item rarity modifier on drops. Increased Item Rarity & Quantity modifiers are only counted from the player who lands the killing blow.

Effect on experience
Only party members that are nearby (roughly two screens) receive experience from a slain monster. If one member is in town or too far from the monster they get no XP. Monsters are still made harder by players elsewhere on the level but outside of XP range.

Effect on flasks and killing blow modifiers
Only the character landing the killing blow gets bonuses from "(...) when you deal a killing blow" type of modifiers. Flasks does not apply to this.

Instances
All areas in Path of Exile are instanced. When you enter an area, a new instance is created. Once you leave the area, the instance will remain in its current state for 15 minutes - if 15 minutes passes with no players entering the instance, it will be closed. This closes any portals you may have had to the area. Entering the same area again will create a new instance with a new randomly generated map. Areas without side areas attached (any area with two or less exits) has a shorter timer, and will only last 8 minutes while empty.

Instances you create are private, and cannot be entered by other players unless they join your party. However, once a player has entered an instance, that instance remains associated with the player even if they leave the party. So it is possible to share an instance with non-party members in some circumstances. The exception to this is towns, which are always public, and cut-throat leagues, where all instances are public - meaning anyone can enter your instances at any time.

Some areas have waypoints. Once activated (by clicking on the waypoint), waypoints allow you to travel instantly to any other waypoint you have activated.

Ctrl-clicking on a waypoint destination in the waypoint menu, or an area transition such as a doorway, will bring up the instance management screen. This screen lists all available instances of the area you ctrl-clicked on, the players inside the instance, and the time remaining until they are closed. It also allows you to create new instances, and enter existing ones. Using the instance management screen you can have more than one instance of the same area open at a time, and choose which available instance you want to enter. This may be useful if one wants to respawn bosses, but note that instances are arranged so that bosses cannot be farmed without traveling a significant distance.

Level difference experience penalty
Level affects the amount of experience you gain from killing enemies, based on the relative level of the player and monsters. A penalty is applied if you are too far above or below the monster level.

=Microtransactions=

Microtransactions are in game digital goods purchased with real world money. Most effects are cosmetic.

Commons options (Does not include everything)
 * Each account is initially limited to 24 character slots, but more can be bought through microtransactions.
 * Skin Transfers can make players appear like they are wearing their favorite looking items, while the actual item they equipped is not shown.
 * Stash tabs can range from basic extra storage, to specific kinds that make storing items easier. For options see stash tab shop