Random Number Generator
Crypto-strong random integers in any range — batch draws, unique or repeated, sorted or raw.
How to use
- Set the min and max of your range.
- Choose how many numbers, and whether repeats are allowed.
- Results generate instantly and re-roll on every change.
Frequently asked questions
Is this really random?
It uses the browser’s Web Crypto API (crypto.getRandomValues), a cryptographically strong source seeded by the operating system — far stronger than Math.random, which is predictable and not suitable for anything security-adjacent.
What does “no modulo bias” mean?
Naive generators do randomValue % range, which slightly favors smaller numbers because 2³² rarely divides evenly by the range. This tool uses rejection sampling: values that would skew the distribution are discarded, so every number in your range is exactly equally likely.
Can I generate negative numbers or decimals?
Negative ranges work fine. Decimals are floored to integers — for random decimals, generate integers in a wider range and divide by a power of ten yourself.
What does “unique” do when the range is too small?
Unique draws without replacement need the count to fit inside the range — asking for 10 unique values from a 5-number range errors out instead of silently duplicating. Turn uniqueness off to allow repeats.
Are there uses this tool is not right for?
Lotteries or contests with legal randomness requirements may demand certified physical RNGs or audited draws. For games, sampling and everyday decisions, this is more than sufficient.