Random Number Generator
Generate random integers, decimals, or unique random numbers within any range. Set the count and copy results instantly.
Random Integer(s)
How to Use This Tool
- Choose a mode: Integer, Decimal, or Coin / Dice.
- For Integer mode, enter a minimum and maximum value, the count of numbers to generate, and optionally enable "No duplicates".
- For Decimal mode, enter a minimum and maximum value, the number of decimal places, and the count.
- For Coin / Dice mode, select coin, D6, D20, or D100, and how many times to flip or roll.
- Click Generate to produce the results, then use Copy to copy them to your clipboard.
Formula & How It Works
Random Integer in Range
result = floor(random() × (max − min + 1)) + minScales a random value between 0 and 1 into a whole number between min and max, inclusive.
Random Decimal in Range
result = random() × (max − min) + minScales a random value between 0 and 1 into a decimal number between min and max, then rounds to the chosen number of decimal places.
Unique Sampling (No Duplicates)
Shuffle the full range, then take the first N valuesEvery integer in the range is placed in a list, randomly shuffled, and the first N are kept so no value repeats.
Practical Examples & Common Use Cases
Example: Random Integer Between 1 and 100
With min = 1 and max = 100, result = floor(random() × (100 − 1 + 1)) + 1. A random() value of 0.42 gives floor(0.42 × 100) + 1 = 43.
Example: Random Decimal Between 0 and 1
With min = 0, max = 1, and 4 decimal places, result = random() × (1 − 0) + 0. A random() value of 0.8173 rounds to 0.8173.
Example: Rolling a D20 Five Times
Selecting D20 with count = 5 generates five independent integers between 1 and 20, e.g. 14, 3, 20, 7, 11.
Frequently Asked Questions
It uses JavaScript's Math.random() to generate pseudo-random numbers uniformly distributed between 0 and 1, then scales and rounds them to the requested range.
They are pseudo-random, generated by a deterministic algorithm seeded by entropy. For cryptographic purposes, use a dedicated CSPRNG. For games, lotteries, and statistical sampling, this is sufficient.
Enabling "no duplicates" ensures each generated number is unique, like drawing numbers from a bag without replacement. The range must contain at least as many values as your requested count.
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