Random Number Generator
Generate random numbers, roll dice, and flip coins. Perfect for games, classrooms, decisions, and more.
Common Uses
| Use | Range |
|---|---|
| Standard die (d6) | 1–6 |
| Percentage | 1–100 |
| Lottery pick (1–49) | 1–49 |
| Card rank (Ace–King) | 1–13 |
| D&D roll (d20) | 1–20 |
| Classroom (30 seats) | 1–30 |
Frequently Asked Questions
A random number generator (RNG) produces numbers that cannot be predicted. Computers use pseudo-random algorithms based on a seed value. Web browsers use the Xorshift128+ algorithm — fast, high-quality, and sufficient for games and sampling. For cryptography, the browser uses a separate secure PRNG (window.crypto.getRandomValues).
Enter 1 in the Min field and 100 in the Max field, then click Generate. Each result is statistically independent — previous numbers do not affect future ones. Every integer from 1 to 100 has an equal 1% chance of appearing on each generation.
2d6 means 2 dice with 6 sides each. The result ranges from 2 (both dice roll 1) to 12 (both roll 6), with an average of 7. This notation is used in board games (Monopoly, Catan), tabletop RPGs (Dungeons & Dragons, Pathfinder), and wargames. 1d20 means one 20-sided die, common in D&D for attack rolls.
A fair coin has exactly 50% probability for heads and 50% for tails on each flip: P(heads) = P(tails) = 0.5. Each flip is independent — getting 5 heads in a row does not make tails 'more likely' on the next flip (gambler's fallacy). Over many flips, the law of large numbers ensures results approach 50/50.