Dice Modifiers: Bonuses, Penalties, and Total Results

Dice modifiers are numbers or rule effects added to or subtracted from a roll. In an expression such as 1d20 + 5, the d20 supplies the random input and 5 is the modifier. The modifier may be a bonus, a penalty, a fixed adjustment, or a value calculated from the character, object, situation, or rule being used.

Read the complete expression

“Roll a d20” and “roll a d20 plus 5” are different instructions. A clear record states the number of dice, the die type, the modifier, the target or comparison, and what happens on the final result. If the modifier is conditional, state when it applies and whether multiple modifiers can be combined.

For example, 2d6 + 3 means roll two six-sided dice, add their face values, and then add 3. It is not the same as 2(d6 + 3), which would add 3 to each die before totaling them. Notation and prose should agree.

Bonuses and penalties

A bonus increases a total, while a penalty decreases it. Some systems use positive and negative numbers; others describe advantage, disadvantage, difficulty, or circumstances without using a visible modifier. DICEWIKI records the actual rule language and avoids assuming that “bonus” always means the same thing across games.

A modifier can affect a check, attack, damage roll, saving throw, table result, or another procedure. The affected step matters. A +2 to an attack roll is not automatically a +2 to damage, and a modifier to a table result may move the selected range rather than change the underlying dice distribution.

Modifiers and probability

Adding a fixed modifier shifts every possible total by the same amount. It does not change the relative spacing between outcomes in a simple model. A d20 with +5 has the same number of possible die faces as a d20 without a modifier, but its total range is different. Conditional rules, rerolls, keep-highest instructions, and caps can change the distribution in more complex ways.

Order and limits

Some rules specify an order: roll dice, apply rerolls, add extra dice, apply modifiers, then compare with a target. Other rules impose a minimum, maximum, floor, ceiling, or special result. Document the order when it changes the answer. A total of 1 may become 3 after a minimum rule, while a natural or face-specific result may retain a special meaning even when the final total is modified.

How to document a modifier

1. Write the full expression, such as 1d20 + 5 or 2d6 – 1.
2. Identify the source of the modifier and the condition for applying it.
3. State the sequence of rerolls, extra dice, bonuses, penalties, and caps.
4. Explain whether the comparison uses the raw roll or the final total.
5. Give one worked example and cite the applicable rules source.

Related DICEWIKI pages

Continue with dice notation, dice mechanics, dice pools, and probability distributions.

Sources and editorial notes

1. D&D Beyond Basic Rules: Playing the Game, for D20 Tests, modifiers, damage, and the need to distinguish a roll from its total.
2. DICEWIKI editorial taxonomy, for separating an expression, its modifier, and its comparison rule.