Random Number Generator
Generate random integers or decimals within any range. Supports multiple numbers and no-duplicate mode.
Random draws: fairness, uniqueness, and cryptographic vs PRNG
Use crypto-backed draws when assigning prizes or secrets. PRNG modes are fine for simulations. “Unique numbers only” prevents duplicate raffle tickets within one batch.
Audit compliance may require external attestation—this page is a convenience utility.
Related tools
These free tools pair well with this page — open them in a new tab to finish your workflow.
Frequently Asked Questions
Is this truly random?
This tool uses window.crypto.getRandomValues(), the browser's cryptographically secure random number generator. It is suitable for security-sensitive applications such as generating lottery numbers, random keys, or nonces. It is not a pseudo-random number generator (PRNG).
What is the difference between PRNG and CSPRNG?
A PRNG (pseudo-random number generator) uses a deterministic algorithm seeded with a value; given the same seed, it produces the same sequence. A CSPRNG (cryptographically secure PRNG) is unpredictable even if you know prior outputs. This tool uses a CSPRNG.
Can I generate the same number twice?
Yes. Each number is drawn independently with equal probability. There is no guarantee of uniqueness unless you specifically need unique numbers and check for duplicates. For a truly unique set, generate in bulk and remove duplicates, or use a shuffle/permutation approach.
What is the maximum range I can use?
This tool supports integers within the safe JavaScript integer range (up to 2^53 - 1). For very large ranges, the random generation remains uniform using BigInt operations internally.
How do I simulate a dice roll?
Set the range to 1–6 for a standard six-sided die. For other dice: 1–4 for a d4, 1–8 for a d8, 1–10 for a d10, 1–12 for a d12, and 1–20 for a d20 (common in tabletop RPGs).