Spell Hit Chance

Spell Hit Chance is an attribute that can be found on items. In general, +1% spell hit chance increases the base chance for a spell to land against a target by 1%. If the target is the same level as the caster, a spell has a base chance to hit of 96%.

Etc...
 * If the target is +1 level compared to caster: 95%
 * If the target is +2 levels compared to caster: 94%
 * If the target is +3 levels compared to caster: 83% if the target is a monster, 87% if the target is a player.
 * If the target is +4 levels compared to caster: 72% if the target is a monster, 80% if the target is a player.
 * If the target is +5 levels compared to caster: 61% if the target is a monster, 73% if the target is a player.

If wearing a +1% spell hit chance item, the above percentages will increase by 1.

For binary spells only, there is an additional modifier for resistance to particular spell schools: fire, frost, shadow, nature, and arcane. That modifier is multiplied by hit chance to get the actual chance to land. This is done with binary spells only, because they never do partial damage.

Example:

Eyonix the Mage (level 60) fires a frost bolt at Yeti of Doom (level 63). Eyonix is also wearing a total of +6% spell hit gear. Yeti of Doom has frost resistance such that he takes 50% from level 60 frost attacks. So, here's the hit calculation:

0.83 (83% for +3 levels monster) + 0.06 (+6% spell hit) = 0.89 0.89*0.5 (50% damage from frost) = 0.445.

The game will roll a number between 0 and 1, and if it's less than 0.445, the frost bolt will hit for full damage. Otherwise, a resist message will appear.

2nd Example:

After the resist, Eyonix decides to fire a fireball at Yeti of Doom. Eyonix still has +6% spell hit. Fireball is not a binary spell. Here's the calculation:

0.83+0.06= 0.89

The game will roll a number between 0 and 1, and if its less than 0.89, the fireball will hit. Otherwise, a resist message will appear. After the fireball lands, the game will then apply spell resistance to determine a partial resist, if any. Assuming the yeti also has 50% fire resistance, on average, 50% of the damage will be resisted.