Random number generator online

What is a random number generator?

A random number generator (RNG) produces numbers that are unpredictable within a chosen range. This page uses strong randomness by default for non-deterministic results and also offers a seed option when you need repeatable sequences for testing or demonstrations. You can generate integers or decimals, enforce uniqueness, exclude specific values, and export your list for further analysis.

How this random number generator works

When no seed is provided, the tool taps into secure randomness available in modern browsers to generate unbiased results across your specified range. If you enable the seed option, it switches to a fast, deterministic algorithm so you can reproduce the same list any time using the same seed, count, and range. Sorting, uniqueness, and exclusion filters are applied after generation to match your exact needs.

Why and when to use it

• Education: Demonstrate probability, sampling, and randomization in class experiments.
• Data tasks: Create synthetic IDs, sample rows, or shuffle sets without bias.
• QA and testing: Generate predictable test data using the seed for repeatable test runs.
• Research: Produce random sequences for simulations and Monte Carlo analysis.
• Everyday picks: Choose winners, assign tasks, or pick numbers fairly.

Best practices for accurate randomization

• Set realistic ranges: Choose a range that fits your task; avoid overly large counts with strict uniqueness that exceed the range capacity.
• Use exclusion thoughtfully: Excluding many values shrinks the effective pool; adjust count or range accordingly.
• Prefer secure randomness: For fairness and unpredictability, use non-seeded mode.
• Use seeds for repeatability: Enable the seed for tutorials, automation, or debugging identical sequences.
• Validate outputs: Export to CSV and verify distributions or duplicates in your analysis tools.

How to use and embed this random number generator

1. Open the tool: Scroll to the top of this page where the generator is located.
2. Set your range: Enter minimum and maximum values that define the interval.
3. Choose count and type: Enter how many numbers to create and select integers or decimals. If decimals, set decimal places.
4. Refine options: Toggle unique/no repeats, sorting, and optionally add an exclude list.
5. Optional seed: Enable “Use seed” and enter any seed string to make results repeatable.
6. Generate: Click Generate. Copy results or download as CSV.
7. Embed (optional): If you want this tool on your site, add a link to this page or embed it via an iframe: <iframe src="https://www.example.com/random-number-generator" title="Random Number Generator" style="width:100%;height:720px;border:0;border-radius:14px;" loading="lazy"></iframe>.

Frequently asked questions

HOW TO generate random numbers without repeats?

Enable “Unique (no repeats)” and ensure your count does not exceed the size of the available range after exclusions. Then click Generate.

HOW TO export random numbers to CSV?

Click “Download CSV” after generation. The file will include one number per line for easy import into spreadsheets or code.

HOW TO get the same random list again?

Toggle “Use seed,” enter a seed value, and keep the same settings (range, count, type). Generating again with the same seed reproduces the exact sequence.

HOW TO generate random decimals?

Select “Decimals,” choose the number of decimal places, and generate. Sorting and exclusions still apply to decimal output.

HOW TO exclude specific numbers?

Enter values in the Exclude field separated by commas or spaces. Excluded values will not appear in your results.

HOW TO sort results ascending or descending?

Use the “Sort ascending” or “Sort descending” options before generating. Leave both off to keep natural randomized order.

HOW TO copy results?

After generation, click “Copy.” The output will be placed on your clipboard using your chosen delimiter.