Random Number Generator

How random numbers are generated here

This tool uses JavaScript's built-in random number generation for general-purpose tasks such as games, sampling, quick experiments, classroom exercises, and ad hoc decision-making. That is appropriate for ordinary browser use, but it is not the same as a cryptographic random generator. If you need secure tokens, passwords, or security-critical randomness, use a dedicated cryptographic source instead.

Single number, list mode, and unique mode

Single-number mode is useful for one-off decisions. List mode generates multiple values and can include repeats. Unique mode samples without replacement, which is what you want for raffle draws, participant assignment, turn order, or any scenario where the same integer should not appear twice. The tool checks the range size first so it does not promise more unique integers than the interval actually contains.

Common use cases

• Pick random winners or assign seats or groups.
• Create sample IDs for demonstrations and tutorials.
• Generate quick test inputs for spreadsheets or code examples.
• Run simple classroom, game, or experiment randomization tasks.

Integer vs decimal output

Use integer mode when the output represents counts, IDs, or draw results. Use decimal mode when you need continuous values, for example when simulating test data, checking rounding behavior, or generating sample inputs for formulas. If you need reproducible sequences for development, this browser tool is the wrong abstraction; use a seeded generator in code instead.

Related tools and guides

• Sample Size Calculator if your randomization task is part of a survey or experiment setup.
• Standard Deviation Calculator to analyze the spread of generated or sampled values.
• Number Sorter if you need to clean and sort a generated list afterward.
• Data Quality Guide for broader advice on preparing synthetic or imported numeric inputs.