Random Number Generator
Adjust the inputs below. Results update as you type.
How it works
Uses a cryptographically secure random number generator (CSPRNG) for fair, unpredictable results—not the pseudo-random Math.random() which is predictable if seeded. Applications: dice simulation, lottery draws, randomized experiments, and statistical sampling. True randomness (hardware-based) differs from pseudo-randomness (algorithmic). For repeated uniform sampling without replacement, use a Fisher-Yates shuffle.
Input guidance
- Check units and decimal placement before running calculations.
- For percentage and ratio tasks, define the baseline value clearly.
- Use rounded output carefully and keep full precision for intermediate steps.
The formula
A random number in a range is min + floor(random × (max − min + 1)) for integers, where random is a uniform value between 0 and 1.
Worked example
To pick a number from 1 to 6 (a die roll): 1 + floor(random × 6), giving each value an equal chance.
More examples to test
- Baseline example: solve with clean numbers first to verify formula direction.
- Edge-case example: test near-zero or boundary values to avoid interpretation errors.
How to interpret results
Use outputs as quick checks, then verify with step-by-step work for graded or high-stakes use.
When this can be inaccurate
Errors usually come from unit mismatch, wrong baseline assumptions, or rounding too early in multistep problems.
Change history
- July 2026: Quality-reviewed for publication with formula checks and explanatory copy updates.
Site-wide corrections also appear on the corrections log.
Build math and logic skills with guided lessons
Educational platform recommendation.
Frequently asked questions
Are these numbers truly random?+
They are pseudo-random — generated by an algorithm that produces statistically random-looking sequences, sufficient for games, sampling, and everyday use.
Can I get a specific range?+
Yes. Set the minimum and maximum, and the generator returns values uniformly distributed within that inclusive range.
Is this good for security?+
Everyday generators are not cryptographically secure. For passwords or keys, use a dedicated secure random source instead.
Why do my classroom and calculator results differ?+
Differences usually come from rounding conventions, order-of-operations handling, or different baseline assumptions.
What is the safest way to validate an answer?+
Recompute with units shown and check against a second method or manual arithmetic for critical problems.