乱数ジェネレーター
Generate cryptographically random numbers in any range.
About This Generator
This random number generator uses the Web Crypto API (crypto.getRandomValues()) for cryptographically strong randomness, making it suitable for passwords, lottery draws, scientific simulations, and any application where true randomness matters. Unlike Math.random(), the Crypto API provides unpredictable values seeded from system entropy.
How It Works
- Set your range: Enter a minimum and maximum value to define the range for generation.
- Choose quantity: Generate a single number or a batch of multiple random numbers at once.
- Set options: Toggle integers vs decimals, allow duplicates or require unique values, and set decimal precision.
- Copy results: Copy the generated numbers in comma-separated, newline-separated, or JSON array format.
Why Use Random Number Generator?
True randomness within a defined range is needed in countless situations: picking lottery numbers, generating test data, selecting a random sample from a list, creating random seeds for simulations, assigning random IDs, or running controlled experiments. Browser-based generation uses crypto.getRandomValues() for cryptographically-strong randomness when security matters, or Math.random() for high-speed generation of large batches. This tool covers both cases and handles ranges from 0–1 decimals to arbitrarily large integers.
Features
- Integer or decimal — whole numbers or floating point values
- Bulk generation — generate up to 10,000 numbers at once
- Unique values — no duplicates option for lottery-style draws
- Export formats — comma-separated, newline, or JSON array
- Cryptographically strong — uses
crypto.getRandomValues()
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