How do I use the Random Number Generator?

Enter the required values, then calculate. The Random Number Generator shows results, formulas, and step-by-step work when available. No account is required.

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How it works

Uniform draws over inclusive ranges. Integers support very large bounds; decimals use a fixed-point grid. Pseudo-random (not cryptographic).

n = min + ⌊U·(max−min+1)⌋ · decimals via 10^p grid

When to use

Use this tool when you need to: simple: roll 1–6. Comprehensive: 6 unique 1–49 (lottery) or 5 decimals in 0–1 with 4-digit precision.

How to use this tool

Enter your values in the fields above.
Review the formula and any mode options for your problem.
Read the result and the step-by-step solution.

Simple: roll 1–6. Comprehensive: 6 unique 1–49 (lottery) or 5 decimals in 0–1 with 4-digit precision.

Frequently asked questions

What is the Random Number Generator?: Uniform draws over inclusive ranges. Integers support very large bounds; decimals use a fixed-point grid. Pseudo-random (not cryptographic).
How do I use the Random Number Generator?: Enter the required values, then calculate. The Random Number Generator shows results, formulas, and step-by-step work when available. No account is required.
What formula does the Random Number Generator use?: n = min + ⌊U·(max−min+1)⌋ · decimals via 10^p grid

Browse categories

Random number generator

Pick a single large integer, or generate one or many integers/decimals with optional uniqueness, sorting, and precision — like a dice roll toolbox.

How it works

What is a random number?

A random number is drawn from a defined pool with no practical pattern for prediction. Consecutive draws are treated as independent. Real-world quantities (like heights) often follow a specific distribution; this tool assumes a uniform distribution over the interval you set.

Uniform range

Both limits are inclusive. Rolling 1–6 can yield 1 or 6. Each integer (or each fixed-precision decimal slot) is equally likely. Hardware randomness (coins, dice) and pseudo-random algorithms (software) are different implementations of the same idea.

Simple vs comprehensive

Simple mode draws a single integer and can use very large bounds (thousands of digits via BigInt). Comprehensive mode can draw many values, allow or forbid duplicates, sort asc/desc, and switch to decimals with a precision setting.

Duplicates and uniqueness

Allowing duplicates is sampling with replacement. Disallowing them is without replacement — like lottery balls. You cannot request more unique values than distinct slots in the range.

Decimals and precision

Decimal mode rounds the interval onto a fixed-point grid (for example, two digits → hundredths). The engine picks a grid index uniformly, then formats the value to the requested number of places.

Pseudo-random note

These generators use the browser’s Math.random — a pseudo-random algorithm, not a hardware entropy source. Fine for games, teaching, and casual sampling. Do not use them for cryptography, security tokens, or regulated lotteries that need audited RNGs.

Related calculators

Use the basic calculator for deterministic arithmetic, or binary/hex tools when working in other bases.

How it works

Uniform draws over inclusive ranges. Integers support very large bounds; decimals use a fixed-point grid. Pseudo-random (not cryptographic).

n = min + ⌊U·(max−min+1)⌋ · decimals via 10^p grid

When to use

Use this tool when you need to: simple: roll 1–6. Comprehensive: 6 unique 1–49 (lottery) or 5 decimals in 0–1 with 4-digit precision.

How to use this tool

Enter your values in the fields above.
Review the formula and any mode options for your problem.
Read the result and the step-by-step solution.

Simple: roll 1–6. Comprehensive: 6 unique 1–49 (lottery) or 5 decimals in 0–1 with 4-digit precision.

Frequently asked questions

What is the Random Number Generator?: Uniform draws over inclusive ranges. Integers support very large bounds; decimals use a fixed-point grid. Pseudo-random (not cryptographic).
How do I use the Random Number Generator?: Enter the required values, then calculate. The Random Number Generator shows results, formulas, and step-by-step work when available. No account is required.
What formula does the Random Number Generator use?: n = min + ⌊U·(max−min+1)⌋ · decimals via 10^p grid

Browse categories

How it works

What is a random number?

Uniform range

Simple vs comprehensive

Duplicates and uniqueness

Allowing duplicates is sampling with replacement. Disallowing them is without replacement — like lottery balls. You cannot request more unique values than distinct slots in the range.

Decimals and precision

Decimal mode rounds the interval onto a fixed-point grid (for example, two digits → hundredths). The engine picks a grid index uniformly, then formats the value to the requested number of places.