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Random Number guide

The Random Number Generator produces random integers or decimal numbers within a specific range. It can generate unique numbers without duplicates and supports up to 500 numbers at once.

Worked examples

Generate 5 random integers

  1. Select the "Integers" tab.
  2. Set the Minimum to 1 and Maximum to 100.
  3. Set the Quantity to 5.
  4. Click Generate.
Result: e.g., 42, 17, 99, 3, 67

The tool picks 5 random integers between 1 and 100. Duplicates are allowed by default.

Generate unique lottery numbers

  1. Select the "Integers" tab.
  2. Set the Minimum to 1 and Maximum to 50.
  3. Set the Quantity to 6.
  4. Uncheck "Allow Duplicates".
  5. Click Generate.
Result: e.g., 7, 14, 22, 31, 44, 50

This acts like a lottery draw, ensuring no number is picked twice.

Generate random decimal numbers

  1. Select the "Decimals" tab.
  2. Set the Minimum to 0 and Maximum to 1.
  3. Set the Quantity to 3.
  4. Set Decimal Places to 4.
  5. Click Generate.
Result: e.g., 0.1452, 0.8921, 0.4431

Generates floating-point numbers uniformly distributed between 0 and 1.

Tips

  • •If generating unique numbers, the Quantity cannot exceed the size of the range.
  • •The tool uses Math.random(), which is pseudo-random (not secure for cryptography).
  • •You can copy all generated numbers at once or save them to your history.

Frequently asked questions

Are these numbers truly random?
They are pseudo-random, generated by JavaScript’s Math.random() function. They appear random and are suitable for games or simulations, but are not cryptographically secure.
What does "Allow Duplicates" mean?
If checked, the same number can be generated multiple times. If unchecked, all generated numbers will be unique.
Why can’t I generate 20 unique numbers between 1 and 10?
Because there are only 10 possible integers in that range. You cannot pick 20 unique numbers from a pool of 10.
What is the difference between integers and decimals here?
Integers are whole numbers (1, 2, 3). Decimals include fractional parts (1.5, 2.75) and allow you to set the precision.
Can I use this for a secure password?
No. Use the dedicated Password Generator tool, which uses the cryptographically secure Web Crypto API.
What is the maximum quantity I can generate?
You can generate up to 500 numbers at a time to prevent browser lag.
How are the decimals rounded?
You can choose between 0 and 6 decimal places. The numbers are rounded to that precision.
What is a uniform distribution?
It means every number in the range has an equal probability of being chosen.
Can the minimum and maximum be the same?
Yes, but if they are, every generated number will be exactly that value.
What happens if I enter a minimum greater than the maximum?
The calculator will show an error asking you to correct the range.
How does the tool avoid duplicates?
When "Allow Duplicates" is off, it creates an array of all possible numbers in the range, shuffles it using the Fisher-Yates algorithm, and takes the first N items.
Can I generate negative numbers?
Yes. You can set the minimum to a negative value (e.g., -100 to 100).
What are random numbers used for?
Statistical sampling, simulations (Monte Carlo), gaming, and generating test data.
Does the tool save my generated numbers?
No, they are lost when you refresh. You must click "Save to History" to keep them.
Can I generate a sequence of consecutive numbers?
Random generation is not consecutive. For consecutive numbers, you would just list them in order.
Why does the result show "e.g." in the guide?
Because the output changes every time you click Generate!
Is Math.random() good enough for Monte Carlo simulations?
For basic educational simulations, yes. For advanced scientific research, a more robust statistical library is recommended.
How do I clear the results?
Just click Generate again to replace the current batch with new numbers.
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