Random number generator

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Generate random numbers online for raffles, simulations, password seeds, sampling, and games. This all-purpose random number generator (RNG) lets you create integers or decimals, pick unique values without repeats, roll virtual dice, flip coins, and even seed results for reproducible tests. Common long-tail needs we cover: random number between two values, random integer generator no duplicates, random decimal generator with precision, and cryptographically secure random number generator online.

What is a Random Number Generator?

A random number generator produces numbers that are unpredictable within a specified range. Our tool supports both pseudo-random (fast and repeatable with a seed) and cryptographically secure modes (suitable for draws and fairness-critical selections). Whether you need a random number between 1 and 100 or a random 6-digit code, you can tailor the output to your use case.

How to use the Random Number Generator

  1. Set the range: minimum and maximum (e.g., 1 to 100 for a random number 1-100).
  2. Choose type: Integer (whole numbers) or Decimal (set precision, e.g., 3 decimal places).
  3. Quantity: generate one value or many (batch mode). Enable no repeats to ensure uniqueness.
  4. Mode: Standard RNG (seedable) or Secure RNG (cryptographic).
  5. Generate and copy/export as CSV/JSON for spreadsheets or scripts.

Popular presets

  • Random integer between two numbers (inclusive): great for giveaways and ticket draws.
  • Random decimal with precision: simulations, A/B testing, probabilities.
  • No-repeat random list: shuffle IDs, student pickers, seating charts.
  • Dice & coin: roll d6, d20, or flip a fair coin online.

Who should use it?

  • Teachers & facilitators: pick a random student, assign groups, shuffle questions.
  • Marketers & event hosts: random winner picker for contests and giveaways.
  • Developers & data teams: sampling, Monte Carlo tests, randomized backoff windows.
  • Gamers & tabletop GMs: dice rolls, loot tables, encounter generators.

Options & settings

Range & inclusivity

Choose inclusive bounds (e.g., 1–100 includes both 1 and 100). For random number 0-1, pick decimals with precision.

Uniqueness & repeats

Enable no duplicates to generate unique numbers (ideal for random number list generator without repeats). Disable to allow repeated draws with equal probability.

Precision & formatting

Set decimal places (e.g., 2 for currency-like outputs). Export as CSV or JSON to integrate with spreadsheets and code.

Seed & reproducibility

Use a seed for repeatable pseudo-random sequences (test runs, demos). Leave blank—or switch to secure RNG—for unpredictable results.

Secure randomness

Select cryptographically secure mode for fairness-critical tasks (raffles, lotteries, security tokens). Note: for passwords/keys, use a dedicated password generator; do not rely on plain numeric RNG.

Best practices

  • Match the mode to the risk: use secure RNG for draws and anything that must not be biased.
  • Document seeds: when reproducibility matters, record the seed and settings with your results.
  • Check constraints: if you need unique values, ensure the requested quantity ≤ range size.
  • Avoid off-by-one: confirm inclusive bounds for “between X and Y” scenarios.

Examples

Common ranges

Random number between 1 and 10   → 7
Random number 1-100 (no repeats) → 34, 91, 3, 76, 58
Random decimal 0-1 (3 dp)        → 0.742

Use cases

# Raffle draw (secure mode)
Range: 1..5000, Quantity: 3, No repeats ✔ → Winners: 128, 4092, 77

# Sampling 20 unique IDs
Range: 1000..9999, Quantity: 20, Seed: 2025 → reproducible list

# Dice & coin
d20 → 15
Coin flip → Heads

FAQ

Is the random number generator truly random?

In standard mode it’s pseudo-random (fast and seedable). In secure mode, it uses a cryptographic source designed for unpredictability.

Does “between X and Y” include both ends?

Yes—our random number between two values setting is inclusive by default (X and Y can appear).

Why can’t I get unique numbers?

If “no repeats” is enabled, your quantity must not exceed the size of the range. For example, 1–10 can supply at most 10 unique values.

Can I reproduce a sequence?

Yes—enter a seed to recreate the same pseudo-random list. Leave seed empty (or use secure mode) for non-repeatable draws.

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