Each ability partially describes your character and affects some of his or her actions.
Every character has six basic Ability Scores:
The Score of these Abilities ranges from 0 to infinity. A limit, if any, will be specified in the rules. The normal human range is 3 to 18. It is possible for a creature to have a score of "none". A score of "none" is not the same as a score of "0". A score of "none" means that the creature does not possess the ability at all. The modifier for a score of "none" is +0.
Keeping track of negative ability score points is never necessary. A characterís ability score canít drop below 0.
Each ability will have a modifier. The modifier can be calculated using this formula:
(ability/2) -5 [round result down]
The modifier is the number you add to or subtract from the die roll when your character tries to do something related to that ability. A positive modifier is called a bonus, and a negative modifier is called a penalty.
Strength measures your characterís muscle and physical power. This ability is especially important for fighters, barbarians, paladins, rangers, and monks because it helps them prevail in combat. Strength also limits the amount of equipment your character can carry.
You apply your characterís Strength modifier to:
Dexterity measures hand-eye coordination, agility, reflexes, and balance. This ability is the most important one for rogues, but itís also high on the list for characters who typically wear light or medium armor (rangers and barbarians) or no armor at all (monks, wizards, and sorcerers), and for anyone who wants to be a skilled archer.
You apply your characterís Dexterity modifier to:
Constitution represents your characterís health and stamina. A Constitution bonus increases a characterís hit points, so the ability is important for all classes.
You apply your characterís Constitution modifier to:
If a characterís Constitution score changes enough to alter his or her Constitution modifier, the characterís hit points also increase or decrease accordingly.
Intelligence determines how well your character learns and reasons. This ability is important for wizards because it affects how many spells they can cast, how hard their spells are to resist, and how powerful their spells can be. Itís also important for any character who wants to have a wide assortment of skills.
You apply your characterís Intelligence modifier to:
A wizard gains bonus spells based on her Intelligence score. The minimum Intelligence score needed to cast a wizard spell is 10 + the spellís level.
An animal has an Intelligence score of 1 or 2. A creature of humanlike intelligence has a score of at least 3.
Wisdom describes a characterís willpower, common sense, perception, and intuition. While Intelligence represents oneís ability to analyze information, Wisdom represents being in tune with and aware of oneís surroundings. Wisdom is the most important ability for clerics and druids, and it is also important for paladins and rangers. If you want your character to have acute senses, put a high score in Wisdom. Every creature has a Wisdom score.
You apply your characterís Wisdom modifier to:
Clerics, druids, paladins, and rangers get bonus spells based on their Wisdom scores. The minimum Wisdom score needed to cast a cleric, druid, paladin, or ranger spell is 10 + the spellís level.
Charisma measures a characterís force of personality, persuasiveness, personal magnetism, ability to lead, and physical attractiveness. This ability represents actual strength of personality, not merely how one is perceived by others in a social setting. Charisma is most important for paladins, sorcerers, and bards. It is also important for clerics, since it affects their ability to turn undead. Every creature has a Charisma score.
You apply your characterís Charisma modifier to:
Sorcerers and bards get bonus spells based on their Charisma scores. The minimum Charisma score needed to cast a sorcerer or bard spell is 10 + the spellís level.
When an ability score changes, all attributes associated with that score change accordingly. A character does not retroactively get additional skill points for previous levels if she increases her intelligence.
CHANGING ABILITY SCORES
Ability scores can increase with no limit.
When an ability score changes, the modifier associated with that score also changes.