Random Number GeneratorFree online math calculator — instant results, no sign-up
Generate random integers in a range.
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About the Random Number Generator
This calculator generates a sequence of pseudo-random integers within a user-specified inclusive range. It is commonly used for lotteries, classroom draws, statistical sampling exercises, and game mechanics requiring unbiased integer selection.
- Min
- The lower bound of the integer range (inclusive), such as 1 or negative integers.
- Max
- The upper bound of the integer range (inclusive), which must be greater than or equal to Min.
- How many
- The quantity of random numbers to generate, capped internally at a maximum of 500.
Formula and method
R = floor(Min + U × (Max − Min + 1))
- RGenerated integer result
- MinMinimum allowed integer value
- MaxMaximum allowed integer value
- UUniformly distributed pseudo-random floating-point value in the half-open interval [0, 1)
The tool repeatedly generates a pseudo-random floating-point number between 0 (inclusive) and 1 (exclusive), scales it across the span from Min to Max plus one, and applies the floor function to produce uniformly distributed integers. The requested count is capped at 500 values, and all output values are sampled independently with replacement.
Worked example
These are the calculator's starting values and the results it actually produces for them.
Inputs
- Min1
- Max100
- How many5
Results
- Numbers8, 17, 50, 91, 79
How to use the Random Number Generator
- 1Define the inclusive bounds by entering values for Min and Max.
- 2Enter the number of random integers you want to generate (up to 500).
- 3Compute each integer using R = floor(Min + Math.random() × (Max − Min + 1)).
- 4Output the generated numbers as a comma-separated list.
Reading your result
The output displays the requested quantity of integers within the specified boundaries, separated by commas. Because each number is generated independently, individual integers can appear multiple times within the same list.
Limitations
The generator performs sampling with replacement, meaning it does not enforce unique values across the output set. It also caps output at 500 numbers per run and relies on standard browser pseudo-random number generation, which is not suitable for cryptographic security.
Common questions
Can the generator produce duplicate numbers?+
Yes. Each number is drawn independently with replacement, so duplicate values can and will occur, especially when generating many numbers from a narrow range.
Are the Min and Max boundaries included in the possible results?+
Yes. Both the Min value and the Max value are inclusive and have an equal probability of being generated alongside any integer between them.
What happens if I ask for more than 500 numbers?+
The tool caps the generation length at 500 numbers per request to prevent browser performance issues.
Does the calculator save my information?+
Calculations run in your browser. While signed in, inputs and results are automatically recorded in account history; saving a result creates a separate saved record.
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Results are estimates for informational purposes and are not financial, medical or legal advice.