Random Number Generator 1 to 20
Pick a number between 1 and 20 at random. Every number has exactly the same 5% chance on every draw. Draw one, or up to 20 at once with no repeats.
Your number appears here.
The odds for 1 to 20, worked out
- Chance of any one number: 1 in 20 (5%)
- Average result over many draws: 10.5
- Same number twice in a row: 1 in 20
- Draws until a repeat is more likely than not: 6
SpinWave draws each number from your browser's cryptographic random source, with rejection sampling so no number in 1 to 20 is favoured. Results are independent. A long run without a particular number does not make it due.
What people use 1 to 20 for
- A twenty-sided die (d20), the core roll for attacks and checks in Dungeons & Dragons.
- Picking one of twenty questions from a worksheet.
How to use this generator
The range on this SpinWave page is already set to 1 to 20. Press Generate for a single number, raise How many to draw several at once, and tick No repeats if nobody should win twice. For any other range, the full random number generator takes whatever minimum and maximum you like. If an audience needs to watch the draw happen, the spin the wheel picker shows it on screen.
Other number ranges
Random number 1 to 20: FAQ
What are the chances of getting a specific number between 1 and 20?
Exactly 1 in 20, or 5%. Every draw is independent, so a number that just came up is no more or less likely next time.
How many draws before a number between 1 and 20 repeats?
With repeats allowed, a repeat becomes more likely than not by draw 6. Tick No repeats to draw up to 20 different numbers in one go.
Does the generator include both 1 and 20?
Yes. Both ends of the range are included, so 1 and 20 can each come up. The average result over many draws is 10.5.