Everyday Math
· Reviewed by Ali Abbas

Random Number Generator

What Are Random Numbers?

A random number is a value generated by a process with no predictable pattern — each outcome is independent of the previous one. Random numbers are fundamental to statistics, gaming, lottery draws, cryptography, scientific simulation, and fair selection processes.

True Random vs Pseudo-Random Numbers

Pseudo-Random (PRNG)

Most computers generate pseudo-random numbers using mathematical algorithms seeded from a starting value. They are statistically uniform and practically indistinguishable from true random for most uses, but are deterministic — the same seed produces the same sequence.

True Random (TRNG)

True random numbers come from genuinely unpredictable physical phenomena — radioactive decay, thermal noise, or atmospheric events. Services like RANDOM.ORG use atmospheric noise. Our generator uses JavaScript's cryptographically seeded PRNG, which is suitable for all non-security uses below.

How to Use This Generator

Enter a minimum and maximum value, choose how many numbers you need, and click Generate. Numbers are uniformly distributed — each has equal probability. Enable No Duplicates for sampling without replacement.

Common Use Cases

Use CaseMinMax
Coin flip01
Standard dice (d6)16
UK National Lottery159
US Powerball (main)169
D&D d20120
Percentage roll1100

Frequently Asked Questions

Is this truly random?

Our generator uses a cryptographically seeded PRNG producing statistically uniform results. For security-critical purposes, use a dedicated cryptographic RNG library.

Can the same number appear twice?

Yes, by default (sampling with replacement). Enable No Duplicates to ensure each number appears only once.

Related Tools

Percentage Calculator — calculate probabilities from your results. GCD & LCM Calculator — explore more mathematical tools.

How to Use

  1. 1
    Choose what to randomiseSelect a tab: Number (range), Multiple Numbers, Dice, Coin Flip, or pick from a custom list.
  2. 2
    Set your parametersFor numbers, enter min and max. For dice, choose type and quantity. For lists, paste your items.
  3. 3
    Click GenerateHit the Generate button to get your cryptographically random result instantly.

Frequently Asked Questions

Is this random number generator truly random?
It uses the Web Crypto API (crypto.getRandomValues()), which is a cryptographically secure pseudo-random number generator (CSPRNG). While technically pseudo-random (generated by an algorithm), it is seeded with hardware entropy and is indistinguishable from true randomness for all practical purposes.
How do I generate a random number between 1 and 10?
Set Min to 1, Max to 10, and click Generate. The result will be a whole number between 1 and 10 inclusive.
Can I generate random numbers without duplicates?
Yes — in the Multiple tab, check the "No duplicates (unique)" option before generating. This ensures each number in your list appears only once.
How do I pick a random winner from a list?
Use the "From List" tab. Enter each participant's name on a separate line, set "How many to pick?" to 1 (or more for multiple winners), and click Pick Random.
What are the odds of rolling a specific number on a D20?
Each face on a D20 (20-sided die) has a 1/20 = 5% probability. Rolling a natural 20 (critical hit in D&D) happens 5% of the time, or roughly once every 20 rolls.
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