Stats and Mods I
Stats and Mods I: How Are They Calculated?
Your Path of Exile character is primarily built from a combination of passive skills, skill gems, and items. Both the passive tree and the items can seem overwhelming at first, so in this tutorial we will cover some of the basics.
The Passive Tree:
The most important thing to know is how the passive tree interacts with your character. In general, passive skills affect all the relevant stats on your character, regardless of where they come from. We call these global modifiers.
In the example above, we see that the 'increased maximum life' passives add together before they affect the character's life. Most passive skills, especially any that use the word 'increased', act this way.
'More' and 'Less':
Passives that specifically say they grant 'more' or 'less' of something are the exceptions to the above rule. These are applied after all of the increases, acting like multipliers. Unlike passives which increase something, passives which provide 'more' or 'less' of something never add together and instead each apply their multiplicative effect separately. These terms appear on Keystones in the passive skill tree, but are most commonly seen on support gems.
Global VS Local:
Item mods tend to come in two varieties: 'global mods', which act like the passive skills, and 'local mods', which affect the item itself. Compare the weapons below, and note that the magic weapon (on the right) has 'Increased Physical Damage'. You'll see that the weapon's Physical Damage is higher, and is a different colour. It is this number that is used when other modifiers, such as your passive skills, are used to calculate how much damage your attacks deal.
The same is true for increases to armour on items that naturally provide armour, or increases to evasion on items that naturally provide evasion, and so on. Some mods, such as 'Increased Attack Speed', can appear on both weapons and armour. Like the Increased Physical Damage modifier, the Increased Attack Speed on the weapon shown below is local to the weapon, and changes that specific weapon's rate of attack. The gloves shown below also have Increased Attack Speed, but they affect any weapon you are holding and use the Attacks Per Second value displayed on the weapon to calculate how quickly you attack.
The attack speed mod on these gloves is a global modifier, so it adds together with other global increases to attack speed, including those on your passive tree. As a general rule (though there are occasional exceptions), if the values in the top section of an item are different to the normal basetype, they are benefitting from local modifiers. If a modifier on an item doesn't seem to be affecting anything in the top section, then it is global. See if you can work out which mods are local and which mods are global in the image below.