Guide
How Random Number Generators Work (and How to Use One)
Learn the difference between random and pseudo-random, how no-repeat mode works, and common uses.
A random number generator picks one or more integers within a range you set. It is used for games, raffles, sampling, and any task that needs an unbiased pick.
Random vs. pseudo-random
Software random number generators are technically pseudo-random — they use a deterministic algorithm that produces a sequence that looks random and passes statistical tests. For games, raffles, and general use this is more than enough. For cryptography, use a generator backed by a cryptographic random source, which the Web Crypto API provides in the browser.
No-repeat mode
When you need several unique picks from a range (drawing raffle tickets, assigning seats), use no-repeat mode. The generator draws without replacement, so each number appears at most once. Without this, the same number can come up twice in a row, which is correct for independent draws but wrong for unique picks.
How to use the generator
- Set the minimum and maximum of the range.
- Choose how many numbers to generate.
- Toggle no-repeat if you need unique picks.
- Read and copy the results.
Examples
Picking a random number from 1 to 6 simulates a die roll. Generating 5 unique numbers from 1 to 49 simulates a lottery draw. Generating a random number from 1 to 100 picks a winner from a class of 100.
When a random number generator is useful
- Running raffles, draws, or giveaways.
- Picking a random sample from a list.
- Simulating dice, cards, or other games.
- Choosing randomly when you cannot decide.
Put it into practice
Use the Random Number Generator right now — free, in your browser, no sign-up required.
Try the Random Number GeneratorMore guides
- How to Unscramble Letters Into Words
- How to Find Anagrams of Any Word
- How to Count Words, Characters and Reading Time Accurately
- How to Find Words by Pattern, Length and Letters
- How to Use a Random Word Generator for Games, Writing and Brainstorming
- How to Count Characters (With and Without Spaces)
- How to Convert Text Between Cases (UPPER, lower, Title, camelCase and More)
- How to Clean Up Messy Text (Spaces, Line Breaks and Whitespace)
Related free tools
More free online utilities that pair well with this one — same-category tools for the same task, plus handy extras from other categories.
More generators tools
- Hash-based Secret Key GeneratorGenerate random API keys & secret tokens
- Dummy Data (JSON/CSV) GeneratorGenerate fake JSON & CSV test data
- Lorem Ipsum GeneratorGenerate placeholder Lorem Ipsum text
- Password GeneratorCreate strong, secure random passwords
- QR Code GeneratorTurn any link or text into a QR code