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HomeUtilityDice Roller

Dice Roller

Roll dice with RPG notation — 2d6, d20+5, 4d6k3, advantage rolls. Free, private, runs in your browser.

100% private — your files never leave your browser. All processing happens locally on your device.

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RPG Dice Notation, Decoded

NdS means 'roll N dice, each with S sides' — 2d6 for two six-sided dice, d20 for a single 20-sided die (N omitted defaults to 1). Modifiers are appended: 2d6+3 rolls two d6 and adds 3. Multiple terms can be combined: 2d6+1d4+5 rolls different dice sizes and sums them. This notation comes from Dungeons & Dragons and is now the common language for any system using dice rolls.

Keep-Highest And Advantage Rolls

NdSkH keeps only the H highest rolls from a set — 4d6k3 is the classic D&D ability-score roll (roll four d6, drop the lowest, sum the rest). 2d20kh1 is D&D 5e's 'advantage' (roll twice, take the better). Use kl for keep-lowest which is 'disadvantage' (take the worse). The notation generalises beyond D&D — any time you want 'best of N' or 'worst of N', keep-highest or keep-lowest expresses it cleanly.

Why Cryptographic Randomness

Most browser-based dice rollers use Math.random() under the hood, which is a seeded pseudo-random generator. For casual dice rolls this is fine, but the distribution isn't truly uniform and it's predictable if you know the browser's seed. This tool uses crypto.getRandomValues() with rejection sampling to eliminate modulo bias. Each die roll is statistically independent and as random as the underlying OS entropy source — same quality used for cryptographic keys.

Session History

The last 20 rolls of the session are kept in view so you can refer back to a previous result without re-rolling. Nothing is saved to disk or sent anywhere; refresh the page and the history resets. Useful during a gaming session when someone asks 'what did I roll for that save?' a few minutes after the fact.

Private, Free, No Signup

No account, no ads, no logging of rolls, no cloud sync. Some players prefer online dice over physical ones for fairness (no loaded d20s), pace (faster than hunting for the right die), or remote play (Discord, Zoom, Roll20 not showing shared dice). This tool works anywhere with a browser — paste the URL into your GM notes and you're set.

FAQ

What notation does it accept?

Standard RPG notation: NdS for N dice of S sides (e.g. 2d6), modifiers with + or − (2d6+3), multiple terms (2d6+1d4+5), and keep-highest/keep-lowest (4d6k3 keeps the 3 best rolls, 2d20kh1 keeps the highest of two — classic D&D advantage; use kl for lowest / disadvantage).

Is it actually random?

Yes. Each die uses crypto.getRandomValues() via a uniform rejection-sampling loop — the same cryptographic randomness browsers expose for key generation. No Math.random(), no predictable PRNGs.

Does it save rolls?

The session history keeps your last 20 rolls for reference. Nothing is persisted to disk or sent anywhere — close the tab and the history's gone.