This section summarizes the statistics that determine success in combat, and then details how to use them.
An attack roll represents your attempt to strike your opponent on your turn in a round. When you make an attack roll, you roll a d20 and add your attack bonus. (Other modifiers may also apply to this roll.) If your result equals or beats the target’s Armour Class, you hit and deal damage.
Automatic Misses and Hits: A natural 1 (the d20 comes up 1) on an attack roll is always a miss. A natural 20 (the d20 comes up 20) is always a hit. A natural 20 is also a threat — a possible critical hit.
Your attack bonus with a melee weapon is:
Base attack bonus + Strength modifier + size modifier
With a ranged weapon, your attack bonus is:
Base attack bonus + Dexterity modifier + size modifier + range penalty
Base Attack Bonus: A base attack bonus is an attack roll bonus derived from character class and level or creature type and Hit Dice (or combinations thereof). Base attack bonuses increase at different rates for different character classes and creature types. A second attack is gained when a base attack bonus reaches +6, a third with a base attack bonus of +11 or higher, and a fourth with a base attack bonus of +16 or higher. Base attack bonuses gained from different sources, such as when a character is a multiclass character, stack.
Strength Modifier: Strength helps you swing a weapon harder and faster, so your Strength modifier applies to melee attack rolls.
Dexterity Modifier: Dexterity measures coordination and steadiness, so your Dexterity modifier applies to attacks with ranged weapons.
Size Modifier: The smaller you are, the bigger other creatures are relative to you. A human is a big target to a halfling, just as an ogre is a big target to a human. Since this same size modifier applies to Armour Class, two creatures of the same size strike each other normally, regardless of what size they actually are.
| Size | Size Modifier |
|---|---|
| Colossal | -8 |
| Gargantuan | -4 |
| Huge | -2 |
| Large | -1 |
| Medium | +0 |
| Small | +1 |
| Tiny | +2 |
| Diminutive | +4 |
| Fine | +8 |
Range Penalty: The range penalty for a ranged weapon depends on the weapon and the distance to the target. All ranged weapons have a range increment, such as 10 feet for a thrown dart or 100 feet for a longbow. Any attack from a distance of less than one range increment is not penalized for range, so an arrow from a shortbow (range increment 60 feet) can strike at enemies up to 59 feet away with no penalty. However, each full range increment causes a cumulative -2 penalty on the attack roll. Thrown weapons, such as throwing axes, have a maximum range of five range increments. Projectile weapons, such as bows, can shoot up to ten increments.
When your attack succeeds, you deal damage. The type of weapon used determines the amount of damage you deal. Effects that modify weapon damage apply to unarmed strikes and the natural physical attack forms of creatures.
Damage reduces a target’s current hit points.
Minimum Damage: If penalties reduce the damage result to less than 1, a hit still deals 1 point of damage.
Strength Bonus: When you hit with a melee or thrown weapon, including a sling, add your Strength modifier to the damage result. A Strength penalty, but not a bonus, applies on attacks made with a bow that is not a composite bow.
Off-Hand Weapon: When you deal damage with a weapon in your off-hand, you add only ½ your Strength bonus.
Wielding a Weapon Two-Handed: When you deal damage with a weapon that you are wielding two-handed, you add 1½ times your Strength bonus. However, you don’t get this higher Strength bonus when using a light weapon with two hands.
Multiplying Damage: Sometimes you multiply damage by some factor, such as on a critical hit. Roll the damage (with all modifiers) multiple times and total the results. Note: When you multiply damage more than once, each multiplier works off the original, unmultiplied damage.
Exception: Extra damage dice over and above a weapon’s normal damage are never multiplied.
Ability Damage: Certain creatures and magical effects can cause temporary ability damage (a reduction to an ability score).
Your Armour Class (AC) represents how hard it is for opponents to land a solid, damaging blow on you. It’s the attack roll result that an opponent needs to achieve to hit you. Your AC is equal to the following:
10 + armour bonus + shield bonus + Dexterity modifier + size modifier
Armour and Shield Bonuses: Your armour and shield each provide a bonus to your AC. This bonus represents their ability to protect you from blows.
Dexterity Modifier: If your Dexterity is high, you are adept at dodging blows. If your Dexterity is low, you are inept at it. That’s why you apply your Dexterity modifier to your AC.
Note that armour limits your Dexterity bonus, so if you’re wearing armour, you might not be able to apply your whole Dexterity bonus to your AC.
Sometimes you can’t use your Dexterity bonus (if you have one). If you can’t react to a blow, you can’t use your Dexterity bonus to AC. (If you don’t have a Dexterity bonus, nothing happens.)
Size Modifier: The bigger a creature is, the easier it is to hit in combat. The smaller it is, the harder it is to hit. Since this same modifier applies to attack rolls, a halfling, for example, doesn’t have a hard time hitting another halfling.
Other Modifiers: Many other factors modify your AC.
Enhancement Bonuses: Enhancement effects make your armour better.
Deflection Bonus: Magical deflection effects ward off attacks and improve your AC.
Natural Armour: Natural armour improves your AC.
Dodge Bonuses: Some other AC bonuses represent actively avoiding blows. These bonuses are called dodge bonuses. Any situation that denies you your Dexterity bonus also denies you dodge bonuses. (Wearing armour, however, does not limit these bonuses the way it limits a Dexterity bonus to AC.) Unlike most sorts of bonuses, dodge bonuses stack with each other.
Touch Attacks: Some attacks disregard armour, including shields and natural armour. In these cases, the attacker makes a touch attack roll (either ranged or melee). When you are the target of a touch attack, your AC doesn’t include any armour bonus, shield bonus, or natural armour bonus. All other modifiers, such as your size modifier, Dexterity modifier, and deflection bonus (if any) apply normally.
Your hit points tell you how much punishment you can take before dropping. Your hit points are based on your class and level, and your Constitution modifier applies. Most monsters’ hit points are based on their type, though some monsters have classes and levels, too.
When your hit point total reaches 0, you’re disabled. When it reaches -1, you’re dying. When it gets to -10, you’re dead.
Your speed tells you how far you can move in a round and still do something, such as attack or cast a spell. Your speed depends mostly on your race and what armour you’re wearing.
Dwarves, gnomes and halflings have a speed of 20 feet (4 squares), or 15 feet (3 squares) when wearing medium or heavy armour (except for dwarves, who move 20 feet in any armour).
Humans, elves, half-elves and half-orcs have a speed of 30 feet (6 squares), or 20 feet (4 squares) in medium or heavy armour.
If you use two move actions in a round (sometimes called a “double move” action), you can move up to double your speed. If you spend the entire round to run all out, you can move up to quadruple your speed (or triple if you are in heavy armour).
Generally, when you are subject to an unusual or magical attack, you get a saving throw to avoid or reduce the effect. Like an attack roll, a saving throw is a d20 roll plus a bonus based on your class, level and an ability score. Your saving throw modifier is:
Base save bonus + ability modifier
Base Save Bonus: A saving throw modifier derived from character class and level. Base save bonuses increase at different rates for different character classes. Base save bonuses gained from different classes, such as when a character is a multiclass character, stack.
Saving Throw Types: The three different kinds of saving throws are Fortitude, Reflex and Will:
Fortitude: These saves measure your ability to stand up to physical punishment or attacks against your vitality and health. Apply your Constitution modifier to your Fortitude saving throws.
Reflex: These saves test your ability to dodge area attacks. Apply your Dexterity modifier to your Reflex saving throws.
Will: These saves reflect your resistance to mental influence as well as many magical effects. Apply your Wisdom modifier to your Will saving throws.
Saving Throw Difficulty Class: The DC for a save is determined by the attack itself.
Automatic Failures and Successes: A natural 1 (the d20 comes up 1) on a saving throw is always a failure (and may cause damage to exposed items; see Items Surviving after a Saving Throw). A natural 20 (the d20 comes up 20) is always a success.