How to use Random Number & Dice
The Random Number & Dice tool has three modes: Number Generator, Dice Roller, and Coin Flip. In Number Generator mode, set your minimum and maximum values, choose how many numbers to generate, and click Generate. The results appear in the output panel. Toggle the Unique checkbox if you need all numbers to be distinct (no repeats) — useful for lottery picks or sampling without replacement.
In Dice Roller mode, select the die type (D4, D6, D8, D10, D12, D20, or a custom-sided die), choose how many dice to roll, and click Roll. Each die's result is shown individually along with the total — convenient for tabletop RPGs, board games, and probability exercises. Coin Flip mode is the simplest: click Flip and get an instant Heads or Tails result with a flip animation.
Why use our Random Number & Dice?
- Three tools in one: number generator, multi-die roller, and coin flip — no need to switch between sites
- Unique number mode for lottery picks, sampling without replacement, and random ordering
- Supports D4, D6, D8, D10, D12, D20, and custom-sided dice
- Multiple dice roll with individual results and a running total
- Uses cryptographically random values via the Web Crypto API
- Three tools in one — random number generator, multi-die roller, and coin flip
Frequently Asked Questions
How random are the numbers generated?
The generator uses window.crypto.getRandomValues(), the browser's cryptographically secure random number generator (CSPRNG). This is the same source of randomness used by HTTPS key generation and secure password managers — it draws entropy from OS-level sources (hardware events, interrupt timing, etc.) that are infeasible to predict or reproduce. For all practical purposes the output is indistinguishable from true randomness.
What does 'unique numbers' mode do?
When Unique is enabled, the generator ensures that no number appears twice in the results. This is equivalent to sampling without replacement: imagine putting all numbers in the range into a hat and drawing them one by one without putting them back. This mode is useful for lottery number picks, creating shuffled ID sequences, randomly ordering items in a list, or any scenario where duplicates would be invalid.
What does D20 (or other die notation) mean?
Dice notation like D6, D20, or 2D8+3 comes from tabletop roleplaying games. The number before D is how many dice to roll; the number after D is how many sides each die has. D6 is a standard six-sided die. D20 is a 20-sided die, commonly used in Dungeons & Dragons. 2D8 means roll two eight-sided dice and sum the results. This tool supports selecting any die type and rolling multiple dice simultaneously, showing each result individually and the combined total.
Is the coin flip truly 50/50?
Yes. The coin flip uses a single random bit from the CSPRNG — if the bit is 0 it's heads, if it's 1 it's tails. With a cryptographically random source, both outcomes have exactly equal probability. There is no bias, no history, and no pattern. Each flip is fully independent of all previous flips — a run of 10 heads in a row does not make tails more likely on the 11th flip (this misconception is called the gambler's fallacy).