Random Number Generator
Generate one or more random integers or six-place decimals between a minimum and maximum. Choose whether repeated values are allowed.
Random Number Generator tool
About the Random Number Generator
Use the generator for practice problems, informal selections, or randomized examples. Values are drawn only when you click Generate, using the browser’s cryptographic random source.
How Is Random Number Calculated?
Integer bounds are rounded inward to the nearest allowed integer. Decimal generation uses an inclusive grid in increments of 0.000001.
When duplicates are disabled, sampling removes each selected grid position from the available pool. This avoids retry loops when the request is close to the size of the range.
Integer grid: low = ceil(min), high = floor(max)
Grid size = high − low + 1
Random index = floor(u × available positions), where 0 ≤ u < 1
Example
For integers from 1 through 6, there are six possible values. Requesting six numbers without duplicates produces a permutation of 1, 2, 3, 4, 5, 6.
How to Use the Random Number Generator
- Enter the minimum and maximum values.
- Choose how many values to generate, from 1 through 1,000.
- Select integers or six-place decimals.
- Choose whether duplicates are allowed.
- Click Generate numbers, then copy the selection or generate another set.
Random Number Generator Examples
Unique integer selection
The inclusive range 10 through 15 contains six integers, so at most six can be requested without duplicates.
Decimal grid
From 0.1 through 0.100002, the six-place grid contains 0.100000, 0.100001, and 0.100002.
Decimal precision
Decimals are sampled from a finite six-place grid, not from a mathematically continuous interval. Very narrow ranges may contain no grid values.
Practical limits
Each request is limited to 1,000 values. Bounds and grid size must fit safe integer precision. Mapping a finite random source to a grid may introduce negligible quantization bias, so this tool does not claim exact unbiased sampling for regulated use.
Frequently Asked Questions
Are both endpoints included?
Yes, if they are representable on the chosen integer or six-decimal grid.
Can I request more unique values than the range contains?
No. The calculator reports the available count instead of repeatedly trying to find impossible new values.
Where does randomness come from?
The click handler uses crypto.getRandomValues in your browser and passes the resulting source to the sampling logic.
Does no duplicates preserve random order?
Yes. Values are returned in draw order, not sorted order, and selected grid values cannot appear again in that set.
Can I use this for passwords or regulated drawings?
No. Although the source is cryptographic, this interface is not a security-token generator or an audited lottery system.