Random number
generator
Pick a range, how many you need, and whether repeats are allowed, powered by your browser's cryptographic random source, with the bias-free math most generators skip.
Prefer a physical calculator?
A few solid picks. As an Amazon Associate, Calculate.to earns from qualifying purchases, at no extra cost to you.
OSALO Desktop Calculator
Extra-large 12-digit LCD, giant buttons, solar + battery, the classic office desk workhorse.
View on Amazon →
Helix Oxford Scientific
240-function scientific calculator for KS3–KS4 maths, with hard cover. Exam-friendly, plastic-free packaging.
View on Amazon →
Casio fx-83GTCW+
The UK classroom-standard scientific calculator (also in pink), allowed in most UK exams.
View on Amazon →
ROATEE Construction Calc
Feet-inch-fraction engineering calculator for carpenters, framers and contractors on site.
View on Amazon →
What "truly random" means here
This generator uses your browser's cryptographic random source (crypto.getRandomValues), the same generator used for encryption keys, rather than the weaker Math.random most sites use. It also applies rejection sampling, which quietly matters:
Both make some numbers slightly more likely than others.
Rejection sampling discards the skewed cases: every value exactly equally likely.
Where people use it
Raffles and giveaways (set no-repeats for multiple winners), random team or seat assignment, sampling rows for a survey, picking lottery-style numbers for fun, classroom problems, and quick decisions with more than two options. Everything runs locally, no draw is transmitted or stored anywhere, so it's private but also unrepeatable: there is no seed and no history.
Honest limits
Browser randomness is excellent for fairness in everyday draws, games and sampling. For anything with legal stakes, regulated lotteries, audited draws, you'd want a documented, witnessed process around the tool, not just the tool. A provably fair generator with SHA-256 receipts, the approach used by the generators on luck.fyi, is one way to give entrants proof they can verify themselves. For two-option decisions the coin flip is quicker, and for names rather than numbers the random picker takes a list directly.
Random number FAQ
It asks the browser's cryptographic generator (crypto.getRandomValues) for raw random values, then maps them to your range with rejection sampling so every number is exactly equally likely, no modulo bias.
It's a cryptographically secure generator seeded by your operating system's entropy, unpredictable for every practical purpose, and far stronger than the Math.random used by most generator sites.
Yes, set duplicates to 'no repeats' and each value appears at most once, ideal for drawing multiple raffle winners. The range must contain at least as many values as you're drawing.
No. Generation happens entirely in your browser; nothing is transmitted, logged or repeatable. Refreshing gives a fresh, unrelated draw.