The Core Mechanic: Whenever you attempt an action that has some chance of failure, you roll a twenty-sided die (d20). To determine if your character succeeds at a task you do this:
If the result equals or exceeds the target number, your character succeeds. If the result is lower than the target number, you fail.
Dice rolls are described with expressions such as “3d4+3”, which means “roll three four-sided dice and add three” (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.
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.
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).
Just about every die roll you make is going to be modified based on your character’s abilities. A tough character has a better chance of surviving a wyvern’s poison sting. A perceptive character is more likely to notice bugbears sneaking up from behind. A stupid character is not as likely to find a secret door that leads to a hidden treasure chamber. Your ability scores tell you what your modifiers are for rolls such as these.
Your character has six abilities: Strength (abbreviated Str), Dexterity (Dex), Constitution (Con), Intelligence (Int), Wisdom (Wis), and Charisma (Cha). Each of your character’s above-average abilities gives you a benefit on certain die rolls, and each below-average ability gives you a disadvantage on other die rolls. When creating your character, you roll your scores randomly, assign them to the abilities as you like, and raise and lower them according to the character’s race. Later, you can increase them as your character advances in experience.
To create an ability score for your character, roll four six-sided dice (4d6). Disregard the lowest die roll and total the three highest ones. The result is a number between 3 (horrible) and 18 (tremendous). The average ability score for the typical commoner is 10 or 11, but your character is not typical. The most common ability scores for player characters (PCs) are 12 and 13. (That’s right, the average player character is above average.)
Make this roll six times, recording each result on a piece of paper. Once you have six scores, assign each score to one of the six abilities. At this step, you need to know what kind of person your character is going to be, including his or her race and class, in order to know how best to distribute the ability scores. Choosing a race other than human or half-elf causes some of these ability scores to change (see the Race Index for information on racial ability modifiers).
The instructions for rolling characters in the previous paragraph is what has become known as the “standard method”. Many Dungeon Masters have alternate methods; consult with your DM for any alternate methods for his or her particular game.
Rolling characters on Roll20: If you are a DM using the Roll20 VTT (Virtual Table Top) system, you can make things easier for you and your players before they create their characters. See Roll20 Character Setup for details.
Each ability, after changes made because of race, has a modifier ranging from –5 to +5. Table: 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.
Mathematically, an ability modifier can be calculated like so:
Where M is the modifier, A is the attribute score, and floor() is a function to round the quotient of A divided by 2 down to the nearest whole integer. This function is built into Roll20.
| Score | Modifier | Bonus Spells (by Spell Level) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| 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… | |||||||||||
The ability that governs bonus spells depends on what type of spellcaster your character is: Intelligence for wizards; Wisdom for clerics, druids, paladins, and rangers; or Charisma for sorcerers and bards. 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.)
Each ability partially describes your character and affects some of his or her actions.
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:
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:
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:
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 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:
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 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:
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 spell’s level.
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, since it affects their ability to turn undead. Every creature has a Charisma score.
You apply your character’s 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 spell’s 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.This rule, like any other in D&D, can be changed by the Dungeon Master, who may declare that a character may indeed gain skill points retroactively, or that doing so counts as training in terms of time and money.
If you’re a new player who is making a new character, you should first have rolled your character’s ability scores as shown above according to your Dungeon Master’s guidelines for his or her particular game. Don’t allocate them just yet. Here’s what to do next.
After you have chosen a race and a class you can allocate your six ability scores to your character’s best advantage, putting high scores where your class needs them most.