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Dice roller and coin flip

Roll up to 20 dice of any common type, type notation such as 2d6+3, and see every die and the total. Switch to coin mode to flip one or many coins and keep count.

Mode

Type of die

Examples: 2d6+3, d20, 4d6kh3 (keep the 3 highest), 2d20kl1 (keep the lowest). Up to 20 dice.

How to use it

  1. Pick the type of die (d4, d6, d8, d10, d12, d20 or d100), the number of dice and an optional modifier.
  2. Or type dice notation such as 2d6+3 or 4d6kh3 into the notation box. The two stay in sync.
  3. Click "Roll". The dice tumble, then show each value and the total.
  4. For a coin, choose "Coin", set how many coins to flip and click "Flip". Heads and tails are counted for you.

What it does

  • Every common die

    d4, d6, d8, d10, d12, d20 and d100, drawn as proper faces; a six-sided die shows pips and the others show numbers.

  • Dice notation

    Type 2d6+3, d20, 1d4+1d6+2 or 4d6kh3 to keep the highest three. Use kl to keep the lowest, dh and dl to drop the highest or lowest.

  • 1 to 20 dice at once

    Roll a handful or a whole pile. Dropped dice are dimmed and crossed out in the breakdown so the total is easy to check.

  • Roll history

    The last 30 rolls are listed with the notation, each die and the total. The list stays on this device until you clear it.

  • Coin flip with counts

    Flip 1 to 20 coins and see heads and tails per throw, plus running totals and percentages that you can reset.

  • Fair and optional sound

    Every die and coin uses your browser's cryptographic random generator. A rattle or coin sound is available and off by default.

Good to know

Dice notation is the shorthand used by tabletop role-playing games. "2d6+3" means roll two six-sided dice, add them and add 3. A d20 roll is common for attack checks, "4d6kh3" (roll four, keep the best three) is a popular way to generate character abilities, and a d100 acts as a percentile roll. Board games, classroom probability lessons and quick decisions all use the same simple idea.

Each roll is independent: earlier results do not change the next one, so a streak of sixes is not a sign that the dice are broken. With enough rolls the results even out, which you can see in the coin counters. The rolls here come from crypto.getRandomValues, the secure generator built into the browser, and an unbiased method turns it into a die face, so every side has exactly the same chance.

Questions and answers

What does 2d6+3 mean?

Roll two six-sided dice, add their values and then add 3. The first number is how many dice, the number after d is how many sides, and the part after + or - is a fixed modifier.

How do I roll with advantage or keep the best dice?

Use keep notation. 2d20kh1 rolls two d20 and keeps the higher one, 2d20kl1 keeps the lower one, and 4d6kh3 keeps the best three of four d6.

How many dice can I roll?

Up to 20 dice in total in one roll, including all parts of an expression such as 2d6+1d8. Each die can have from 2 to 1000 sides; the buttons cover the usual seven types.

Is the dice roller fair?

Yes. Each result comes from the browser's cryptographic random number generator and is converted without bias, so every face is equally likely. Math.random is not used.

Can I flip several coins at once?

Yes. In coin mode choose 1 to 20 coins and click Flip. You see heads and tails for the throw and running counts for the session, which you can reset.

Is my roll history saved or shared?

The history is kept in this browser only, so it is still there after a reload. Nothing is sent to a server, and the Clear history button removes it.

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