Pick a random number between 1 and 20 instantly. Use pool mode to get every number exactly once — no repeats until all 20 have been drawn. Works on any device, no install needed.
A random number from 1 to 20 is drawn with equal probability — each of the 20 integers has a 5% chance on every generate. The 1–20 range is one of the most versatile in everyday use: it covers a standard classroom row, a small team raffle, and the classic "I'm thinking of a number" guessing game. This tool uses JavaScript's Math.random(), seeded from hardware entropy, to produce unbiased results every time.
Pool mode for small groups
Pool mode shuffles all 20 numbers into a private queue using the Fisher-Yates algorithm. Each click draws the next number without replacement — guaranteeing every number appears exactly once before the pool resets. It is ideal for calling on students in a class of up to 20, assigning unique numbers in a small raffle, or any situation that requires guaranteed fairness across a short range.
Common uses for 1–20
The 1–20 range covers guessing games ("pick a number between 1 and 20"), scoring in classroom quizzes, turn order in board games for up to 20 players, and assignment of numbered seats or roles. The exclude feature lets you remove numbers that don't apply — for example, if your team has 15 people, exclude 16–20 to keep picks within your group size.
Frequently asked questions
Is this random number generator truly random?
This tool uses Math.random(), a pseudorandom number generator built into every modern browser. It is seeded from hardware entropy and produces outputs that pass statistical randomness tests — more than sufficient for games, raffles, and classroom use.
What is pool mode?
Pool mode picks each number from 1 to 20 exactly once, like drawing from a hat without replacement. Once all 20 numbers have been picked, the pool reshuffles automatically. This ensures no repeats until every number has been drawn.
Can I exclude specific numbers?
Yes. Click "Exclude numbers" and enter a comma-separated list. The generator will never produce those numbers. In pool mode, excluded numbers are removed from the pool before shuffling.
How is this different from the 1–100 generator?
This page is optimized for the 1–20 range specifically. The distribution chart groups results into pairs (1–2, 3–4, …), pool mode handles 20 numbers, and all pool tracking reflects the smaller range. For a wider range, see the 1–100 generator or the custom range generator.
Who uses this tool
Teachers
Call on students in a small class with pool mode — every student gets called exactly once before the pool resets. Perfect for groups of up to 20.
Game players
Decide turn order, run guessing games, or settle tiebreakers. The 1–20 range is a classic for number-guessing games between friends.
Event organizers
Draw winners from a pool of up to 20 tickets. Use pool mode for guaranteed-unique winner draws with no repeats.
Students
Use the distribution chart to verify uniform randomness over the 1–20 range. Each pair of numbers should appear roughly equally over many generates.