A character's skill ranks in a skill is based on how many skill points a character has invested in a skill. For class skills, 1 point = 1 rank; for cross-class skills, 1 point = 1/2 rank. Ranks are the base to which other modifiers, such as skill focus and an ability modifier, are added.
Many skills can be used even if the character has no ranks in them; doing this is called making an untrained skill check.
- There is a +50 cap to skill bonuses. This only includes magical bonuses from spells and items, not the ability modifier nor bonuses from feats (e.g. alertness).
- The maximum skill level possible is 127, counting all items, ranks, feats, and ability score modifiers. This is a limitation of the game engine, which assigns only an 8-bit number to tracking this (half of the range is relegated to negative numbers, and one number is, of course, zero).