Random Number Generator
Generate random numbers within a range
Set a min and max range
floor(random() x (max - min + 1)) + minWhat is a Random Number Generator?
A Random Number Generator (RNG) is a tool that produces numbers unpredictably within a range you choose. You set a minimum value and a maximum value, and the tool generates a random number between them. This is useful for games, picking winners, making random selections, simulating outcomes, and testing software.
Random number generators are often used to avoid bias when choosing something. For example, you can randomly select a number to decide a turn order, generate random quiz questions, pick a raffle winner, or create random test data for programming and spreadsheets.
Generator Options
This tool lets you set a Min and Max value and generates a random integer within that range. More advanced RNG tools may also support:
- Count -- how many random numbers to generate at once
- Decimals -- generate decimal numbers instead of integers only
- Unique numbers -- ensure no duplicates in the generated set
Most online RNG tools use a pseudo-random algorithm, which means the numbers are generated by a mathematical process that appears random. For everyday uses—like giveaways, classroom activities, games, and testing—this is more than sufficient.
How to Use This Random Number Generator
- Enter the minimum value (Min) -- the lowest number that can be generated
- Enter the maximum value (Max) -- the highest number that can be generated
- Click "Calculate" -- to generate your random number
- Review the result -- a random integer within the specified range is displayed
- Generate again -- click Calculate again for a new random number each time
Tips:
- Make sure Min is less than Max—the tool needs a valid range to generate from
- If you enable unique numbers (on tools that support it), the count cannot exceed the size of the range (e.g., you cannot generate 20 unique integers from 1 to 10)
- Results will change each time you generate -- this is expected for a random tool
Formulas
Random Integer (Inclusive Range)
A basic way to generate a random integer between Min and Max (inclusive):
Random Integer = ⌊Random(0,1) × (Max − Min + 1)⌋ + Min
Random(0,1) -- a random decimal from 0 up to (but not including) 1
⌊ ⌋ -- floor function (round down)
Random Decimal (Continuous Range)
For generating decimal values within a range:
Random Decimal = Random(0,1) × (Max − Min) + Min
No floor function needed for decimal results
A Note on Randomness
Most online tools produce pseudo-random numbers using algorithms. For typical use (games, classroom, random picks, test data), this is perfectly fine. If you need cryptographic security (passwords, encryption keys), use a security-focused generator.
Example Calculations
Example 1: One Random Integer from 1 to 10
Min: 1, Max: 10
Output: any whole number: 1, 2, 3, …, 10
Example result: 7 (your result will vary)
Example 2: Five Random Integers from 100 to 200
Min: 100, Max: 200, Count: 5
Possible output: 112, 198, 145, 160, 101 (results vary)
Example 3: Three Unique Integers from 1 to 5
Min: 1, Max: 5, Count: 3, Unique: ON
Possible output: 2, 5, 1 (no repeats)
Example 4: Random Decimal from 0 to 1
Min: 0, Max: 1, Decimals: ON
Possible output: 0.3729 (results vary)
Frequently Asked Questions
Are the numbers truly random?
Most online random number generators use pseudo-random algorithms, which produce results that look random for everyday purposes. For games, raffles, and testing, they are typically sufficient.
Why do I sometimes see repeated numbers?
If "unique numbers" is off, repeats are allowed. Even with randomness, repeats can occur naturally—especially when the range is small.
What does "unique numbers" mean?
It means the generator will not repeat the same number in the output set. This is useful for picking distinct winners or creating non-duplicated selections.
What happens if Min is greater than Max?
The input is invalid. The tool will require you to correct the values. Always ensure Min ≤ Max.
Can I use this for passwords or security keys?
For security-sensitive use, you should use a cryptographically secure generator (often labeled "secure random" or "crypto-safe"). A general RNG is best for non-security uses like games, simulations, and random picks.
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