# Online:Spell Critical (effect)

Spell Critical is a value that represents your chance of performing a Critical Strike when attacking with a Staff weapon or casting spells (skills which cost Magicka). Your actual chance of performing such a strike also depends on your level - it is harder to strike critically the higher your level. The formula[1] (all are identical - they are provided to aid ease of understanding) for determining the Maximum Critical Value (MCV) required to gain 100% Critical strike chance is:

``` MCV = (2 * Level * (100 + Level))))
MCV = (2*(100*Level + Level2))))
MCV = (2*(100*Level + Level2))))
```

You start with a baseline 10% critical value, so the amount of Spell Critical needed from buffs to get 100% Critical Strike Chance is 0.9 * MCV. This means at level 50 you need 13,500 Spell Critical to have a 100% chance (an extra 90%). At CP160 (level 66) you need 19721 Spell Critical. Your Critical Strike Chance% is then computed from:

``` Critical Strike Chance% = min(100,10 + 100*(Critical Value / MCV))
```

You cannot have a worse than 10% chance (because 10% is your baseline) or better than 100% chance to critically strike. So if you are CP160 and have a Spell Critical of 3000, your Critical Strike Chance% = 10 + 100 * (3000 / 21912) = 23.7%

There are a large number of skills and sets which increase your Spell Critical rating. See those categories for a complete listing. In addition, there are a few other ways of increasing your Spell Critical rating:

The Critical Damage, or amount of increased damage or healing from Critical Strikes is normally 50% of the base strike. So at 10% chance, your strikes are 1.05x their listed effectiveness, while at 100%, they are 1.5x. Factors which increase your Weapon Critical Damage include: