What Makes an Online Randomizer Fair?

Fairness starts with the source

A randomizer first needs a value that is difficult to predict. Real Randomizer uses the Web Crypto API supplied by the browser rather than Math.random for its core draws. That API is designed to provide cryptographically strong values suitable for security-sensitive software.

Mapping values without bias

A secure value still needs to be mapped into a smaller range. A simple remainder operation can make some outcomes slightly more common when the original range is not divisible by the target range. Our bounded integer routine rejects the small portion of values that would cause this modulo bias, then maps the accepted value into your chosen interval.

The animation is only a reveal

Wheels, coins and rolling effects make a result easier to follow, but the visual should not control the selection. The outcome is chosen by the random routine and the animation presents it.

Use the right level of assurance

Browser tools are useful for classes, games, sampling, giveaways and everyday choices. Regulated lotteries, elections and audited financial processes need purpose-built controls and independent verification.

Try the Random Number Generator or compare the full set in the tool directory.