Random Numbers
Random Numbers is a browser-based dice roller and random picker. It accepts tabletop dice notation, numeric ranges, or custom option lists and shows the result with a short animation and a history of past rolls.
Random selection tasks often need more than a single final result. This tool handles dice rolls, draws from a set, and simple random picks without storing anything server-side.
What it solves
Random selection tasks often need more than a single final result. This tool handles dice rolls, draws from a set, and simple random picks without storing anything server-side.
It also makes each result easier to review by showing the evaluation steps, including how dice expressions are reduced and how arithmetic is applied.
Features
- Presets One-tap presets cover a dice roll, coin flip, card draw, Magic 8-Ball, and dice sizes from d4 through d100.
- Dice notation It accepts standard dice expressions with arithmetic and parentheses, including exploding, keeping, and dropping modifiers.
- Ranges It can pick a value from a numeric range written with two dots, including negatives and decimals.
- Custom sets It can choose from options pasted as separate lines, pipe-separated values, or comma-separated values.
- Roll mode It picks with replacement.
- Draw mode It picks and removes the result from the set.
- Graph mode It runs 1,000 simulations and shows a bar chart of the outcome distribution with percentages.
- Details panel It shows each evaluation step, including individual die rolls and the math passes that follow.
- History It keeps a session table of previous rolls.
- Query prefill A query parameter can prefill the input.
How to use it
- Enter a dice expression, numeric range, or list of options.
- Or choose one of the preset buttons.
- Select Roll to get a result.
- Use Draw when the chosen item should be removed from the set.
- Open Details to review each step of the calculation.
- Use Graph to view the simulated outcome distribution.
How it works
- It runs entirely in the browser.
- Dice expressions are parsed by a hand-written interpreter that repeatedly resolves dice tokens and then evaluates arithmetic with parentheses and operator precedence.
- Dice modifiers are parsed for exploding, dropping, and keeping results, with protection against infinite explode loops.
- Random die values use cryptographic random number generation instead of
Math.random. - The rolling animation performs repeated re-rolls before recording the final result, and Graph mode builds its frequency table on the client.