Random number generator
Generate random integers or floats in any range. Single or batch output with optional no-repeat and sort. Powered by the Web Crypto API.
100% in your browser. Numbers generated locally, nothing sent.
Output
How to use
- Set the minimum and maximum bounds for the range.
- Enter the count of numbers you want to generate.
- Choose Integer for whole numbers or Float for decimal values.
- Enable No-repeat for unique values (useful for lotteries and raffles).
- Click Generate, then Copy to use the output.
Common use cases
- Lottery picks — no-repeat integers in a competition range.
- Random sampling — pick N random indices from a dataset.
- Simulation — float values for Monte Carlo or probability models.
- Classroom exercises — generate quiz numbers or random student IDs.
Also see: Random String Generator for text tokens, UUID Batch Generator for unique identifiers.
Preguntas frecuentes
- Is the number generation truly random?
- Yes. The generator uses crypto.getRandomValues() for unbiased randomness, the same source used for cryptographic applications. It is not pseudorandom like Math.random().
- What is the maximum range I can use?
- For integers, the range can span up to Number.MAX_SAFE_INTEGER (9,007,199,254,740,991). Very large ranges use BigInt internally to avoid modulo bias. For floats, the range is limited to standard IEEE 754 double precision.
- What does "no-repeat" mean?
- When no-repeat is enabled, the batch will not contain duplicate values. The count must be no greater than the total integers in the range. For floats, no-repeat is disabled because duplicates are extremely unlikely already.
- Can I generate numbers for a lottery or raffle?
- Yes. Set the range to match the lottery draw (e.g. 1–49), enable no-repeat, and generate the required count. The output is as random as your browser's crypto API allows.
- What is the difference between integer and float mode?
- Integer mode returns whole numbers with no decimal part. Float mode returns numbers with up to 6 decimal places, useful for probability simulations, coordinates, or sampling.
- Can I download the output?
- Use the Copy button to copy the list to the clipboard. You can then paste it into a spreadsheet or text file. A dedicated CSV download may be added in a future version.
- Are the numbers sorted?
- By default, numbers appear in generation order (random). Enable "Sort output" to display them in ascending numeric order.
- How many numbers can I generate at once?
- Up to 10,000 per batch. Generating very large batches may take a moment for no-repeat validation over small ranges.