Random Number Generator
Generate random integers or decimals within a specified range. Configurable inclusive/exclusive bounds.
Random Number Generator
Generate a truly random integer within any range
How to Use the Random Number Generator
Generate a truly random integer within any range in just a few clicks.
Define your minimum and maximum values to establish the bounds. Every integer between these two values is a possible outcome.
Select how many numbers you need in a single generation. You can produce one result at a time or batch-generate a larger set for sampling or analysis.
Enable unique mode to prevent duplicate numbers from appearing in your results. Disable it if you want each draw to be fully independent and allow repeats.
Click Generate to produce your random numbers, then use the Copy button to save them to your clipboard. Hit Again to instantly create a new batch.
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How the Random Number Generator Works
Behind the simple interface lies a robust randomness engine built on modern browser APIs.
Randomness Source
This tool uses crypto.getRandomValues() rather than Math.random(). The Web Crypto API draws entropy directly from your operating system's hardware-level sources, producing numbers that are cryptographically secure. Math.random() uses a deterministic algorithm and is unsuitable for any application where unpredictability matters.
Uniform Distribution
To guarantee equal probability for every integer in your range, the generator rejects biased samples. It calculates a rejection threshold based on the range size, discards any raw value that would introduce bias, and redraws until a fair result is obtained. This ensures each number truly has a one-in-N chance of being selected.
Uniqueness Enforcement
When unique mode is enabled, the generator maintains a set of already-emitted values. After each draw, it checks whether the result has already appeared. If a duplicate is detected, the value is discarded and a new random draw occurs immediately. This cycle repeats until the requested count of distinct numbers is fulfilled.
Frequently Asked Questions
Is this random number generator cryptographically secure?
Yes. It relies on the Web Crypto API, which pulls entropy from your operating system's hardware random number generator. This is the same level of randomness used in TLS certificates, encryption keys, and security tokens.
Can I generate numbers with repeats?
Absolutely. Leave unique mode disabled and the tool will draw each number independently. The same value can appear multiple times, just like rolling a die several times in a row.
What is the maximum count I can generate at once?
The tool can produce up to 1,000 numbers per generation. For very large batches in unique mode, the range must be at least as large as the requested count to avoid an impossible constraint.
Does the range include both the minimum and maximum values?
Yes, the range is fully inclusive. If you set min to 1 and max to 100, both 1 and 100 are possible results. Every integer in between also has an equal chance of being selected.
Can I use this for lottery or raffle draws?
Yes. Assign each participant a number and generate a winner using this tool. For high-stakes draws, screen-record the generation to provide transparent proof that the selection was unbiased.
Is my data stored on any server?
No. Every calculation happens locally in your browser. Nothing is transmitted to a server, and refreshing the page clears all generated results and history.