Random Number Generator

How to use this calculator

Use the basic section for one inclusive whole number, or configure quantity, precision, uniqueness, sorting, and separators in the custom section.
Review the live result and use Copy result when you need to share it.

How the calculation works

The generator maps secure browser random values into the requested range with rejection sampling to avoid modulo bias. Unique batches use sampling without replacement, and decimal uniqueness is based on the final displayed precision.

Formula

Unbiased value = minimum + secure sample within the inclusive range

Step-by-step calculation

Use the basic section for one inclusive whole number, or configure quantity, precision, uniqueness, sorting, and separators in the custom section.
The generator maps secure browser random values into the requested range with rejection sampling to avoid modulo bias. Unique batches use sampling without replacement, and decimal uniqueness is based on the final displayed precision.
Check the displayed result, then copy it if needed.

Worked example

Choose 1 to 10 with quantity 6 and duplicates disabled to generate six unique lottery-style numbers. For decimal data, choose 0 to 1, quantity 20, and two decimal places.

Risk guidance

What a random number generator does

A random number generator selects values without asking you to choose each one. This tool supports fast single-number draws and configurable batches for games, samples, test data, classroom exercises, and everyday decisions.

Inclusive ranges and number types

Both minimum and maximum are eligible results. Whole-number mode selects integers; decimal mode selects from the values representable at your chosen 0-to-10 decimal precision, including zero and negative ranges.

Generating unique values

When duplicates are disabled, each final formatted value appears once. The tool checks capacity before generating and explains when the requested quantity is impossible for the range and precision.

Security and randomness

Modern browsers provide crypto.getRandomValues for stronger randomness than Math.random. Rejection sampling avoids modulo bias. A Math.random fallback is used only when the secure browser API is unavailable.

Uses and limitations

The results suit general-purpose draws, examples, testing, and simulations. They are not a substitute for regulated lottery or gambling equipment, audited scientific systems, cryptographic key management, or any process requiring certified randomness.

Copying and downloading

Copied and downloaded results preserve the selected new-line, comma, space, or custom separator. All output remains plain text and is generated locally.

Frequently asked questions

Are the minimum and maximum included?

Yes. Both ends of the range can be generated.

Can I generate negative random numbers?

Yes. Minimum and maximum may be zero or negative.

Can I generate unique numbers without duplicates?

Yes. Disable duplicates; the tool validates that enough distinct formatted values exist.

Can I generate decimal numbers?

Yes. Decimal mode supports zero to ten displayed decimal places.

Is this random number generator secure?

It prefers crypto.getRandomValues and removes modulo bias, but it is not a certified system for regulated or key-management use.

Can I download the generated numbers?

Yes. Download TXT preserves your selected separator.

Does this tool send my inputs anywhere?

No. The interactive calculation runs in your browser and this site does not submit tool inputs to a backend.

How should I use the result?

Check that the entered units and values match your situation, especially around dates, breaks, and rounding.

Basic random number generator

Custom random number generator