乱数生成
任意の範囲で乱数を生成。複数の数値・ユニーク値・カスタム範囲に対応。
関連キーワード
How to Use Random Number Generator
Random numbers have many practical uses: picking lottery numbers, simulating dice rolls for games, selecting a random winner from a list, generating test data, running statistical simulations, or simply making a fair decision when you can't choose between options. Our Random Number Generator uses JavaScript's Math.random() function to generate numbers within any range you specify. You can generate a single number or a batch of up to 1,000 numbers at once. Enable 'No duplicates' mode to ensure each generated number is unique within the range — useful for lottery-style picks or sampling without replacement. All generated numbers can be copied with a single click.
- 1
Set your range and count
Enter the minimum value, maximum value, and how many numbers to generate.
- 2
Enable unique mode (optional)
Check 'No duplicates' if you need unique values — for example, lottery number picks.
- 3
Generate and copy
Click the Generate button. A single large number is displayed prominently, or multiple numbers appear as a list you can copy.
Frequently Asked Questions
Are the numbers truly random?
The tool uses Math.random(), which is a pseudo-random number generator (PRNG). It is suitable for games, simulations, and everyday use but not for cryptographic purposes. For cryptographic randomness, use the Password Generator which uses crypto.getRandomValues().
What is the maximum number of values I can generate at once?
You can generate up to 1,000 numbers at once. If 'No duplicates' is enabled, the count cannot exceed the size of the range (max − min + 1).
Can I generate decimal (floating point) numbers?
Currently the tool generates integers only. Decimal support may be added in a future update.