The Basics

The Core Mechanic

Whenever you attempt an action that has some chance of failure, roll a twenty-sided die (d20). To determine if your character succeeds at a task you:

  • Roll a d20.
  • Add any relevant modifiers.
  • Compare the result to a target number.

If the result equals or exceeds the target number, your character succeeds. If the result is lower than the target number, he fails.

Dice

Dice rolls are described with expressions such as "3d4+3," which means "roll three four-sided dice and add 3" (resulting in a number between 6 and 15). The first number tells you how many dice to roll (adding the results together). The number immediately after the "d" tells you the type of die to use. Any number after that indicates a quantity that is added or subtracted from the result.

d%: Percentile dice work a little differently. You generate a number between 1 and 100 by rolling two different ten-sided dice. One (designated before you roll) is the tens digit. The other is the ones digit. Two 0s represent 100.


Modifiers

A modifier is any bonus or penalty applying to a die roll. A positive modifier is a bonus, and a negative modifier is a penalty.

Stacking

In most cases, modifiers to a given check or roll stack (combine for a cumulative effect) if they come from different sources and have different types (or no type at all), but do not stack if they have the same type or come from the same source (such as the same spell cast twice in succession). If the modifiers to a particular roll do not stack (overlap), only the best bonus and worst penalty applies. Dodge bonuses and circumstance bonuses however, do stack with one another unless otherwise specified.

Modifiers

A modifier is any bonus or penalty applying to a die roll. A positive modifier is a bonus, and a negative modifier is a penalty.

Ability: The bonus or penalty associated with a particular ability score. Ability modifiers apply to die rolls for character actions involving the corresponding abilities.

Armor: An armor bonus applies to Armor Class and is granted by armor or a spell or magical effect that mimics armor. Armor bonuses stack with all other bonuses to Armor Class (even with natural armor bonuses) except other armor bonuses. An armor bonus doesn't apply against touch attacks, except for armor bonuses granted by force effects (such as the mage armor spell) which apply against incorporeal touch attacks, such as that of a shadow.

Circumstance: A circumstance bonus (or penalty) arises from specific conditional factors impacting the success of the task at hand. Circumstance bonuses stack with all other bonuses, including other circumstance bonuses, unless they arise from essentially the same source.

Competence: A competence bonus (or penalty) affects a character's performance of a particular task, as in the case of the bardic ability to inspire competence. Such a bonus applies to attack rolls, skill checks, caster level checks, or any other checks to which a bonus relating to level or skill ranks would normally apply. It does not apply on ability checks, damage rolls, initiative checks, or other rolls that aren't related to a character's level or skill ranks.

Craft: A craft bonus is applied to items and affects a character's performance of a particular task using that item. Such a bonus applies to attack rolls, damage rolls, or skills checks.

Deflection: A deflection bonus affects Armor Class and is granted by a spell or magic effect that makes attacks veer off harmlessly. A deflection bonus applies against touch attacks.

Dodge: A dodge bonus improves Armor Class (and sometimes Reflex saves) resulting from physical skill at avoiding blows and other ill effects. Any situation or effect (except wearing armor) that negates a character's Dexterity bonus also negates any dodge bonuses the character may have. Dodge bonuses stack with all other bonuses to AC, even other dodge bonuses.

Enhancement: An enhancement bonus represents an increase in the sturdiness and/or effectiveness of armor or natural armor, the effectiveness of a weapon, or a general bonus to an ability score. Multiple enhancement bonuses on the same object (in the case of armor and weapons), creature (in the case of natural armor), or ability score do not stack. Since enhancement bonuses to armor or natural armor effectively increase the armor or natural armor's bonus to AC, they don't apply against touch attacks.

Insight: An insight bonus improves performance of a given activity by granting the character an almost precognitive knowledge of what might occur. Insight bonuses apply to any action or situation for which foresight or increased awareness would apply – attack rolls, Armor Class, Reflex saves, and skill checks.

Luck: A luck modifier represents good (or bad) fortune. Luck modifiers can apply to any roll that has a random chance of success – attack rolls, saving throws, skill checks, caster level checks, etc., but not Armor Class or damage rolls.

Morale: A morale bonus represents the effects of greater hope, courage, and determination (or hopelessness, cowardice, and despair in the case of a morale penalty). Morale modifiers apply to attack rolls and skill checks, or most other checks to which a bonus relating to level or skill ranks would normally apply.

Nonintelligent creatures (creatures with an Intelligence of 0, or no Intelligence at all) are not affected by morale modifiers.

Natural Armor: A natural armor bonus is a bonus to Armor Class resulting from a creature's naturally tough hide. Natural armor bonuses stack with all other bonuses to Armor Class (even armor) except other natural armor bonuses. Natural armor can receive an enhancement bonus from spells like barkskin, in which case the adjusted natural armor bonus is used instead of the normal one. A natural armor bonus doesn't apply against touch attacks.

Racial: A bonus granted to certain creatures or races because of their innate characteristics. If a creature's race changes (for instance, if it dies and is reincarnated), it loses all racial bonuses it had in its previous form.

Resistance: A resistance bonus affects saving throws, providing extra protection against harm.

Shield: A shield bonus improves Armor Class and is granted by a shield or by a spell or magic effect that mimics a shield. Shield bonuses stack with all other bonuses to AC except other shield bonuses. A shield bonus granted by a spell or magic item typically takes the form of an invisible, tangible field of force that protects the recipient. A shield bonus doesn't apply against touch attacks.

Size: A size bonus or penalty is derived from a creature's size category. Size modifiers apply to Armor Class, attack rolls, Stealth checks, and combat maneuver checks.


Rounding Fractions

In general, if you wind up with a fraction, round down, even if the fraction is one-half or larger.

Exception: Certain rolls, such as damage and hit points, have a minimum of 1.


Multiplying

Sometimes a rule makes you multiply a number or a die roll. As long as you're applying a single multiplier, multiply the number normally. When two or more multipliers apply to any abstract value (such as a modifier or a die roll), however, combine them into a single multiple, with each extra multiple adding 1 less than its value to the first multiple. Thus, a double (×2) and a double (×2) applied to the same number results in a triple (×3, because 2 + 1 = 3).

When applying multipliers to real-world values (such as weight or distance), normal rules of math apply instead. A creature whose size doubles (thus multiplying its weight by 8) and then is turned to stone (which would multiply its weight by a factor of roughly 3) now weighs about 24 times normal, not 10 times normal. Similarly, a blinded creature attempting to negotiate difficult terrain would count each square as 4 squares (doubling the cost twice, for a total multiplier of ×4), rather than as 3 squares (adding 100% twice).


Ability Scores


Ability Modifiers

Each ability, after changes made because of race, has a modifier ranging from –5 to +5. Table 1: Ability Modifiers and Bonus Spells shows the modifier for each score. It also shows bonus spells, which you'll need to know about if your character is a spellcaster.

The modifier is the number you apply to the die roll when your character tries to do something related to that ability. You also use the modifier with some numbers that aren't die rolls. A positive modifier is called a bonus, and a negative modifier is called a penalty.

Table 1: Ability Modifiers and Bonus Spells

Bonus Spells (by Spell Level)
Score Modifier 0 1st 2nd 3rd 4th 5th 6th 7th 8th 9th
1 -5 Can't cast spells tied to this ability
2–3 -4 Can't cast spells tied to this ability
4–5 -3 Can't cast spells tied to this ability
6–7 -2 Can't cast spells tied to this ability
8–9 -1 Can't cast spells tied to this ability
10–11 0
12–13 +1 1
14–15 +2 1 1
16–17 +3 1 1 1
18–19 +4 1 1 1 1
20–21 +5 2 1 1 1 1
22–23 +6 2 2 1 1 1 1
24–25 +7 2 2 2 1 1 1 1
26–27 +8 2 2 2 2 1 1 1 1
28–29 +9 3 2 2 2 2 1 1 1 1
30–31 +10 3 3 2 2 2 2 1 1 1
32–33 +11 3 3 3 2 2 2 2 1 1
34–35 +12 3 3 3 3 2 2 2 2 1
36–37 +13 4 3 3 3 3 2 2 2 2
38–39 +14 4 4 3 3 3 3 2 2 2
40–41 +15 4 4 4 3 3 3 3 2 2
42–43 +16 4 4 4 4 3 3 3 3 2
44–45 +17 5 4 4 4 4 3 3 3 3

etc…

Abilities And Spellcasters

The ability that governs bonus spells depends on what type of spellcaster your character is: Intelligence for wizards; Wisdom for clerics, druids, and rangers; or Charisma for bards, paladins, and sorcerers. In addition to having a high ability score, a spellcaster must be of high enough class level to be able to cast spells of a given spell level. (See the class descriptions for details.)

When an ability score changes, all attributes associated with that score change accordingly.

The Abilities
Each ability partially describes your character and affects some of his or her actions.


Strength (Str)

Strength measures your character's 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 character's Strength modifier to:

  • Melee attack rolls.
  • Damage rolls when using a melee weapon or a thrown weapon (including a sling). (Exceptions: Off-hand attacks receive only one-half the character's Strength bonus, while two-handed attacks receive one and a half times the Strength bonus. A Strength penalty, but not a bonus, applies to attacks made with a bow that is not a composite bow.)
  • Climb, Jump, and Swim checks. These are the skills that have Strength as their key ability.
  • Strength checks (for breaking down doors and the like).


Dexterity (Dex)

Dexterity measures hand-eye coordination, agility, reflexes, and balance. This ability is the most important one for rogues, but it's 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 character's Dexterity modifier to:

  • Ranged attack rolls, including those for attacks made with bows, crossbows, throwing axes, and other ranged weapons.
  • Armor Class (AC), provided that the character can react to the attack.
  • Reflex saving throws, for avoiding fireballs and other attacks that you can escape by moving quickly.
  • Acrobatics, Disable Device, Stealth, Ride, and Sleight of Hand checks. These are the skills that have Dexterity as their key ability.


Constitution (Con)

Constitution represents your character's health and stamina. A Constitution bonus increases a character's hit points, so the ability is important for all classes.

You apply your character's Constitution modifier to:

  • Each roll of a Hit Die (though a penalty can never drop a result below 1 - that is, a character always gains at least 1 hit point each time he or she advances in level).
  • Fortitude saving throws, for resisting poison and similar threats.
  • Concentration checks. Concentration is a skill, important to spellcasters, that has Constitution as its key ability.

If a character's Constitution score changes enough to alter his or her Constitution modifier, the character's hit points also increase or decrease accordingly.


Intelligence (Int)

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. It's also important for any character who wants to have a wide assortment of skills.

You apply your character's Intelligence modifier to:

  • The number of skill points gained each level. (But your character always gets at least 1 skill point per level.)
  • Appraise, Craft, Decipher Script, Knowledge, Search, and Spellcraft checks. These are the skills that have Intelligence as their key ability.

A wizard gains bonus spells based on her Intelligence score. The minimum Intelligence score needed to cast a wizard spell is 10 + the spell's level.

An animal has an Intelligence score of 1 or 2. A creature of humanlike intelligence has a score of at least 3.


Wisdom (Wis)

Wisdom describes a character's willpower, common sense, perception, and intuition. While Intelligence represents one's ability to analyze information, Wisdom represents being in tune with and aware of one's 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 character's Wisdom modifier to:

  • Will saving throws (for negating the effect of charm person and other spells).
  • Heal, Perception, Profession, Sense Motive, and Survival checks. These are the skills that have Wisdom as their key ability.

Clerics, druids, and rangers get bonus spells based on their Wisdom scores. The minimum Wisdom score needed to cast a cleric, druid, or ranger spell is 10 + the spell's level.


Charisma (Cha)
Charisma measures a character's 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 and paladins, since it affects their ability to turn undead. Every creature has a Charisma score.

You apply your character's Charisma modifier to:

  • Checks that represent attempts to influence others.
  • Bluff, Diplomacy, Disguise, Gather Information, Handle Animal, Intimidate, Perform, and Use Magic Device checks. These are the skills that have Charisma as their key ability.

Bards, paladins, and sorcerers get bonus spells based on their Charisma scores. The minimum Charisma score needed to cast a bard, paladin, or sorcerer spell is 10 + the spell's level.



XP Table

Alignment

Races

Classes

Prestige Classes

Skills

Feats

Unless otherwise stated, the content of this page is licensed under Creative Commons Attribution-ShareAlike 3.0 License