Choose a range, then generate locally.
For casual decisions and simulations only. Not for regulated gaming, lotteries, audits, certifications, or cryptographic key generation.
This tool runs locally in your browser. Inputs and results are not transmitted or retained by BoringToolsKit.
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What does this calculator estimate?
Random number generator: pick random integers or decimals in any range, with or without duplicates, for draws, games, sampling. Free, runs in your browser.
How this calculator works
Formula
Worked example
Assumptions to verify
Frequently asked questions
What is a random number generator?
A random number generator is a tool that produces unpredictable numbers within a range you choose, using mathematical algorithms to ensure each number has an equal chance of appearing.
Do I need to create an account or sign up?
No, this random number generator runs entirely in your browser with no signup, no registration, and no data stored on any server.
Is the random number generator truly random?
It uses a pseudo-random algorithm, which is statistically unpredictable and fair for everyday use, but it is not suitable for cryptographic or security-critical purposes.
Cite this tool
BoringToolsKit. “Random Number Generator.” boringtoolskit.com/random-number-generator/ (reviewed July 2026). Free to reference in articles, syllabi, and answer posts with a link.
Privacy: Inputs and results stay in this browser. Any future sponsored recommendation or advertisement will be clearly labeled and kept separate from the calculation.