How to Use Dice in Tabletop RPGs

The basic D20 check

Many role-playing games resolve uncertain actions by rolling a D20, adding a relevant modifier, and comparing the total with a target. The game master calls for a roll only when success is uncertain and failure has a meaningful consequence. A total meeting or exceeding the difficulty class succeeds.

Suppose a locked gate has difficulty 14. A character with a +3 bonus rolls 12, producing 15 and succeeding. A natural face and a final total are not the same: “natural 12” names the die itself, while 15 is the result after modifiers.

Attack rolls, ability checks, and saving throws may all use this structure, but their special rules differ. A natural 20 may be special for an attack without automatically succeeding on every ability check. Always follow the rules of the system being played.

Modifiers and difficulty

A modifier represents training, attributes, equipment, conditions, or situational help. Add bonuses and subtract penalties after the die settles. On Dice Row, the Roll Modifier changes the displayed total while leaving each individual die result visible.

These examples assume that meeting the target succeeds and ignore automatic-success rules. Every +1 changes a normal D20 success chance by five percentage points until the required natural face moves outside the die's range.

Advantage and disadvantage

For D20 advantage, roll two D20s and keep the higher face. For disadvantage, keep the lower. Do not add the dice together. Advantage raises the average result and reduces the chance of a very low face; disadvantage does the reverse.

Use this mechanic only when the game's rules grant it. Multiple sources often do not stack, and one source of advantage may cancel one or more sources of disadvantage. Dice Row's RPG Roller exposes the choice directly so both physical results remain visible while the kept result determines the total.

Damage, healing, and mixed dice

Damage rolls commonly use D4, D6, D8, D10, or D12 dice. The notation 2d8 + 4 means roll two D8s, add both faces, then add four. Critical-hit rules vary: some double the dice, some double the final total, and others maximize part of the roll. Confirm the system rule before building the pool.

Several smaller dice create consistent middle results. One larger die creates a flatter distribution with more frequent extremes. A weapon dealing 2d6 and one dealing 1d12 have similar maximums, but 2d6 rolls 7 most often while every D12 face is equally likely.

Mixed expressions can be rolled in one tray. Keep the individual result list visible so players can apply resistance, rerolls, exploding dice, or damage types correctly instead of relying only on a grand total.

Percentile rolls and random tables

A percentile roll produces 1 through 100. Physical sets often use one D10 for tens and another for ones; “00” and “0” together usually mean 100. A labeled D100 in a digital roller reports the final percentage directly.

Game masters use percentile tables for encounters, treasure, weather, reactions, or downtime events. Define the ranges without gaps or overlaps. If 01-20 means calm weather and 21-45 means rain, every outcome has a clear interpretation and rain has a 25% chance.

Good digital dice etiquette

Build the pool where everyone can see it, state bonuses before the roll, and wait for the dice to settle. Use roll history to resolve a missed result, not to reroll an unfavorable one. Clear history between unrelated sessions when players want a clean record.

Digital dice are also useful for remote play, limited table space, low-light rooms, and players who find small markings difficult to read. They should support the shared fiction rather than interrupt it: prepare common pools as presets and keep the roller within easy reach.