True Random Number Generator
Understand where real randomness comes from and draw numbers from your device entropy source.
True Random Number Generator
Number from 1 to 100
Range
How many numbers
How to use the true random generator
- Set the range and how many numbers you need.
- Turn on no repeats for a unique set, and sort if you want it ordered.
- Generate, then copy or export.
What is a true random number generator
A true random number generator draws numbers from your device entropy source and explains where real randomness actually comes from. Set your range and count for a draw seeded by genuine hardware entropy, and read on to understand how that differs from the formula driven randomness most software uses.
True random vs pseudo random numbers
Not all randomness is the same. The difference is where the unpredictability comes from, and whether the sequence could ever be repeated.
| Type | Source | Repeatable |
|---|---|---|
| True random | physical noise, such as radioactivity or atmospheric static | no |
| Cryptographic (this tool) | operating system entropy, seeded from hardware | not in practice |
| Pseudo random | a maths formula from a seed | yes, from the same seed |
A pure software formula is deterministic: start it from the same seed and it retraces the same path exactly. A true random source draws on physical events that cannot be replayed, which is what this generator taps through your operating system.
Where the entropy comes from
Your device continuously gathers unpredictable signals: the precise timing of keystrokes and mouse moves, disk and network events, and dedicated hardware noise on modern chips. The operating system pools this entropy and uses it to seed its cryptographic generator, which is what the browser exposes and what this page draws from. For everyday purposes, picking winners, sampling, or generating keys, the result is as good as true random.
Why true random numbers are unbiased
Every draw uses rejection sampling so that no number in the range is favoured by rounding, and nothing you enter leaves your device. For the same source described for security use, see the secure random number generator, and for a repeatable sequence from a seed, the seeded generator.
More number generators
Frequently asked questions
Is this really true random
It draws from your browser cryptographic entropy source, which is seeded by unpredictable system events. For any everyday purpose the results are effectively true random.
How is it different from a normal generator
In practice it uses the same high quality source. The difference is mainly in how the randomness is described and where the entropy comes from.
Can I block repeats
Yes. Tick no repeats for a set of distinct numbers, capped at the size of the range.
Does anything leave my device
No. Every draw happens in your browser and nothing you enter is sent anywhere.
Is it free
Yes, free and with no sign up.
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For the same source described for security use, see the secure random number generator, or the everyday random number generator.