Random Number Generator: Custom Range, Quantity, and Format Tool
From lottery draws to dice simulations, statistical sampling to test data generation — random numbers are needed everywhere. Our generator gives you full control: set any integer range, choose how many numbers to generate, allow or prevent duplicates, and export in four formats.
All generation happens instantly in your browser with no server required.
Random number generation algorithm:
Common Use Cases
Lottery simulation: Generate 6 unique numbers from 1-49 (or your local lottery range)
Dice rolling: Generate 1-6 with duplicates for any board game
Random sampling: Generate unique indices to randomly select items from a list
Test data: Generate IDs, ages, prices, or quantities for database seeding
Raffles: Generate unique ticket numbers or winner picks
Decision making: Let random numbers settle disputes or make choices
Output Format Guide
Space Separated: 30 45 31 6 36 11 - easy to read
Newline Separated: One per line - paste into spreadsheets
Comma Separated: 30, 45, 31, 6 - use in SQL WHERE IN clauses
JSON Array: [30,45,31,6] - use in APIs and developer tools
Practical Examples
Lottery draw
- 1.Preset: Lottery Numbers (1-49)
- 2.Duplicates: Off (each ball drawn once)
- 3.Format: Space Separated
- 4.Result: 6 unique numbers 1-49 sorted
Random sampling
- 1.Min: 0, Max: array length - 1
- 2.Count: Sample size needed
- 3.Duplicates: Off for unique indices
- 4.Use: Select random items from any list
Frequently Asked Questions
Are the numbers truly random?
The generator uses JavaScript's Math.random() which is a pseudo-random number generator (PRNG). It is statistically random enough for games, simulations, sampling, and most practical applications. For cryptographic purposes (e.g., generating keys or secrets), use crypto.getRandomValues() instead.
What is the difference between duplicates allowed and no duplicates?
With duplicates allowed, each number is drawn independently - the same number can appear multiple times (like rolling a die multiple times). With no duplicates (like a lottery draw), each number can only appear once. The generator uses a Fisher-Yates shuffle to ensure a fair, unbiased unique selection.
How many numbers can I generate at once?
You can generate up to 1000 numbers at once. For unique number generation, the maximum is capped by the size of the range (max - min + 1). For example, if your range is 1-10, you can generate at most 10 unique numbers.
What output formats are available?
Space Separated: numbers on one line separated by spaces (default). Newline Separated: one number per line. Comma Separated: numbers joined by commas - useful for CSV or SQL IN clauses. JSON Array: valid JSON array format - useful for developer tools and APIs.
How do I use this for a lottery draw?
Use the Lottery Numbers (1-49) preset or set Min to 1, Max to your lottery's highest number, set Count to the numbers needed, and disable duplicates. The generator uses a shuffle algorithm to ensure all combinations are equally likely.
Can I generate random decimals or floats?
Currently the generator produces integers only. For decimal numbers, generate integers and divide by a power of 10. For example, generate numbers 1-100 and mentally divide by 10 to get one decimal place values (0.1-10.0).
What is a good use case for the PIN Code preset?
The PIN Code (0-9) preset generates 4 random digits with duplicates allowed (since PINs can repeat digits). This is useful for generating test PIN codes, OTP examples, or teaching probability concepts.
What does the sorted view show?
Below the generated output, a sorted view shows the same numbers arranged in ascending order. This is especially useful for lottery-style draws where you want to see the numbers in order for easy reading and verification.