Free Random Number Generator Online - Custom Range, Integers & Decimals
Generate random numbers within a custom range. Supports integers and decimals.
Range Settings
Format Settings
Click Generate to create a random number
Key Features
🎲 Cryptographically Secure
Uses crypto.getRandomValues() for true randomness, not Math.random().
📐 Custom Range
Set any minimum and maximum values, including negative numbers.
🔢 Integer or Decimal
Choose between whole numbers or specify decimal precision from 1 to 15 places.
📋 Bulk Generation
Generate up to 1000 random numbers at once for batch needs.
How to Use Random Number Generator
Set Range
Enter the minimum and maximum values for your random numbers.
Choose Options
Select Single or Multiple mode, and choose Integer or Decimal with the desired precision.
Generate and Copy
Click "Generate" and copy the result or download as a file.
💡 Example
To simulate rolling a 6-sided die:
- Set Min=1, Max=6
- Select Integer mode
- Choose Single mode
- Click Generate to get a random number between 1 and 6
💡 Tip: Enable Real-time mode to automatically generate new numbers when you change any settings.
Frequently Asked Questions
Basics
How random is the generated number?
This random number generator uses `crypto.getRandomValues()`, a cryptographically secure pseudorandom number generator (CSPRNG) provided by modern web browsers. It is far more random and unpredictable than `Math.random()`, which is not suitable for security-sensitive applications. The numbers generated are uniformly distributed across your specified range, ensuring each possible value has an equal chance of being selected. This generator is suitable for cryptography, lottery simulations, statistical sampling, scientific applications, and any use case requiring high-quality, unpredictable random values.
Can I set a custom range?
Yes, you can set any custom range by entering minimum and maximum values. Both negative numbers and decimals are supported. The random number generated will always fall inclusively between your specified min and max values. For integer mode, the range includes both endpoints (e.g., min=1, max=6 generates 1,2,3,4,5, or 6). For decimal mode, the range is continuous, generating any value between min and max. The tool validates that min is not greater than max and provides helpful error messages.
What is the difference between integer and decimal mode?
Integer mode generates whole numbers only (e.g., 5, 42, 100). Decimal mode generates numbers with fractional parts (e.g., 3.14, 2.718). In decimal mode, you can control the number of digits after the decimal point (precision). Integer mode is ideal for IDs, dice rolls, random sampling, and counts. Decimal mode is ideal for measurements, percentages, physics simulations, and continuous random variables.
Advanced Features
How many decimal places can I specify?
You can specify between 1 and 15 decimal places. The default is 2 decimal places. Keep in mind that higher precision reduces the number of distinct possible values within a fixed range. For most applications, 2-6 decimal places is sufficient. For statistical or scientific applications, you can use up to 15 decimal places for maximum precision.
Can I generate multiple random numbers at once?
Yes, this random number generator supports bulk generation. Switch to Multiple mode and set the quantity (1 to 1000 numbers). The tool will generate that many random numbers instantly, displayed as a scrollable list. You can copy individual numbers using the copy icon next to each result, copy all numbers at once (in your chosen output format: one per line, comma-separated, JSON array, or CSV), or download them as a file. Bulk generation is perfect for test data creation, statistical simulations, Monte Carlo methods, and batch processing needs.
Is this random number generator secure for sensitive applications?
Yes, because it uses `crypto.getRandomValues()`, which is a cryptographically secure random number generator (CSPRNG). This means the generated numbers cannot be predicted by an attacker, making them suitable for security-sensitive tasks such as generating session tokens, password reset codes, CSRF tokens, cryptographic nonces, random salts for password hashing, API keys, and verification codes. Never use `Math.random()` for these purposes, as its output can be predicted. This tool is also privacy-safe — all generation happens locally in your browser with no data transmission.
Can I generate unique random numbers without duplicates?
Yes, enable the "Unique numbers (no duplicates)" option in Multiple mode. This ensures all generated numbers are distinct from each other. This feature is available when generating integers and when the range size (max - min + 1) is greater than or equal to the requested quantity. Use cases include random sampling without replacement, lottery or sweepstakes winners (no duplicate tickets), assigning unique random IDs to users, generating random quiz questions without repeats, and creating random sequences from a fixed set. The tool automatically warns you if the range is too small for the requested quantity of unique numbers.