Dice Roller

What this rolls

Standard tabletop and RPG dice, d4, d6, d8, d10, d12, d20, and d100, singly or in groups. Pick the number of dice, the type, and a modifier. Or switch to expression mode and type the dice notation directly: 3d6+2 means roll three six-sided dice and add 2 to the total.

The expression parser accepts the standard notation used in D&D and most pen-and-paper RPGs:

• 1d20, one twenty-sided die
• 3d6, three six-sided dice (the classic stat roll)
• 3d6+2, same plus a modifier
• 2d20-1, two d20s with a negative modifier
• 4d6, common for ability scores (some game masters say “drop the lowest”)

Dice can have between 2 and 1,000 sides, and you can roll up to 100 at once. The result panel shows individual rolls in addition to the total, useful when you need to know which die came up nat 20.

Why use a virtual dice roller

Three real reasons people land here:

1. Online tabletop games: Roll20, Foundry, Discord-based campaigns. Voice GMs need a roller everyone can see.
2. Lost or scattered dice: anyone who’s ever rolled under the couch knows.
3. High dice counts: rolling 50d6 by hand is tedious. The simulator does it instantly and shows every result.

The roll history (last 30 rolls) helps in long sessions when you need to remember whether a previous attack hit, or to settle disputes about whose turn rolled what. History clears when you reset or close the tab.

Cryptographic randomness vs. real dice

This roller uses crypto.getRandomValues, the browser’s secure random number generator, for every die. That’s actually more uniformly random than a real physical die, since real dice can have weight imbalances, worn edges, or “dead” sides from being dropped. Casino dice are precision-machined for a reason.

For most tabletop play this difference is irrelevant. It matters more when:

• You’re rolling thousands of dice for statistical analysis
• Someone in the group is suspicious about a “lucky” string of rolls (the sim is provably uniform)
• You’re using dice mechanics in a video game and need uniform output

D&D-flavored quick reference

Common dice mechanics you’ll roll here:

• Ability score: 4d6, drop the lowest die, repeat 6 times for a character
• Skill check: 1d20 + ability modifier vs. DC
• Attack roll: 1d20 + attack bonus vs. AC
• Damage: weapon dice + ability modifier (e.g. 1d8+3 longsword damage)
• Critical hit: roll damage dice twice (e.g. crit with 1d8 weapon = 2d8 + modifier)
• Saving throw: 1d20 + save modifier vs. spell DC
• Death save: 1d20, succeed on 10 or higher

For Pathfinder, Call of Cthulhu, FATE, or other systems with non-d20 mechanics, the expression mode handles whatever notation your rulebook uses.

What “advantage” and “disadvantage” look like

D&D 5e introduced advantage (roll 2d20, take the higher) and disadvantage (roll 2d20, take the lower). The roller doesn’t do this automatically yet, to simulate advantage, roll 2d20 and pick the higher of the two displayed dice. To simulate disadvantage, take the lower.

Frequently asked questions

Why does my crit roll feel “rare”? A natural 20 on a single d20 is exactly 5% probable. Over 100 rolls, expect about 5 nat 20s, but they’ll cluster, not space out evenly. Streaks of “no nat 20s for 25 rolls” are completely normal even with a perfectly fair die.

Can I share a roll with someone? Not directly, the roller is local. For verifiable shared rolls in tabletop sessions, integrated rollers in Roll20 / Foundry / Discord bots have audit trails this tool doesn’t.

What about exploding dice / re-rolls / Wild Magic surges? Not built in. For complex mechanics, use Roll20 or a system-specific dice bot. This roller is intentionally simple, it does standard dice notation and stops there.

Why is d100 different from d10? d100 rolls a single result from 1 to 100. Some rulebooks use “percentile dice”, two d10s where one represents tens and one represents ones, but the modern convention is to roll a single d100 for simplicity. Same outcome distribution either way.