Weight

Weight is a game mechanic that is a central part of many other systems found in Path of Exile, including how item drop rate, modifier roll chance, and in Ruthless mode, Extra Content spawn rate.

Overview

Weight systems are used when the chance for an outcome is dependent on the ratio between other outcomes. These systems work by assigning a number (weight) to each rollable outcome, and the weight is compared to the sum of all outcomes' weights to create a ratio. For example, if a modifier with a weight of 1000, and a total weight of 40,000, that modifier has a 2.5% chance to roll (1000/40,000).

The weight system also can apply to systems without data-mineable weights, such as the chance to encounter a master in a map. In these cases, an arbitrary weight can be assigned equally to all outcomes for the purpose of calculating ratios.

Modifying weights

When multiplying weights, the total weight must always be increased or decreased the same amount as the individual weights. This causes the written multiplier to be different from the actual change.

All similar modifiers with "increased" or "reduced" must be added together before applying the multiplier.

The following modifiers are examples of modifiers that are a more multiplier to weights:

Source	Modifier	Multiplier
Fossils	More X modifiers	10x
Prismatic FossilPrismatic FossilStack Size: 20More Elemental modifiers No Physical Ailment or Chaos Ailment modifiersPlace in a Resonator to influence item crafting.	More Elemental modifiers	6x
Divination Scarab	#% more Divination Cards found in Area	1.5-3.5x
Reliquary Scarab	#% more Unique Items found in Area	1.5-3.5x
Physical Training, Higher Education, The Fine Arts	Heist Contracts found in your Maps are 100% more likely to require X	2x
Cartography Scarab	#% increased Maps found in your Maps	Stackable
Breach passives	Breaches in your Maps have #% increased chance to belong to X	Stackable
Hunting Season, Mining Partnership, Archaeology Tour, Covert Stakeouts	Master Missions from completing your Maps have #% increased chance to be X Randomly encountered Masters in your Maps have #% increased chance to be X	2x
League mechanic passives in Ruthless	Your Maps have #% increased chance to contain X (Mechanic encounter rates are dependent on each other in Ruthless)	Stackable

The following modifiers are examples of modifiers that are a less multiplier to weights:

Source	Modifier	Multiplier
Fossils	Fewer X modifiers	0.15x
Harvest passives	Harvest Crops in your Maps have #% reduced chance to grow X Plants	Stackable

The following modifiers are examples of modifiers that null weights to 0:

Source	Modifier	Multiplier
Fossils	No X modifiers	0x
League mechanic blocking notables in Ruthless	Your Maps have no chance to contain X (Mechanic encounter rates are dependent on each other in Ruthless)	0x

Example ▾ [Expand] ▾

Example of modifying weights

Using a fictional example:

Assume that Crimson Temple MapCrimson Temple MapMap Level: 79
Map Tier: 12
Guild Character: ©A sanguine supplication to death and depravity.Travel to this Map by using it in a personal Map Device. Maps can only be used once. only contains two cards: The Blazing FireThe Blazing Fire6Chin SolLethal, untouchable, keen, aflame. Just what I was looking for. and The ApothecaryThe Apothecary5Mageblood"You seek the power of my strongest potions, but the price will be far higher than you can imagine.".

• The total weight of all DropPool items is 8000000.
• The Blazing Fire has a drop weight of 12586. This means 0.157% _{(12586 / 8000000)} of items dropped will be The Blazing Fire.
• The Apothecary has a drop weight of 7. This means 0.0000875% _{(7 / 8000000)} of items dropped will be The Apothecary.

Using a causes the weights of Divination cards to be multiplied by 3.5 (250% more).

• The Blazing Fire now has a drop weight of 44051. _{(12586 * 3.5)} This adds 31465 to the DropPool. _{(44051 - 12586 = 31465)}
• The Apothecary now has a drop weight of 24. _{(7 * 3.5)} This adds 17 to the DropPool. _{(24 - 7 = 17)}
• The total weight of all DropPool items is now 8031472.
• This means 0.548% _{(44051 / 8031472)} of items dropped will be The Blazing Fire. The actual chance to drop was multiplied by 3.49, not 3.50. _{(0.548 / 0.157)}
• This means 0.000299% _{(24 / 8031472)} of items dropped will be The Apothecary. The actual chance to drop was multiplied by 3.42, not 3.50. _{(0.000299 / 0.0000875)}