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Random Number Generator

Generate random numbers between any range. Choose integer or decimal, with or without duplicates, sorted or unsorted, single or multiple values. Free online random number generator.

Last revised 24 August 2026

By Team GlobalCalqulate · About our editorial standards

Range Settings

Minimum Value

The smallest possible number (inclusive).

Maximum Value

The largest possible number (inclusive for integers, exclusive for decimals).

Generation Options

How Many Numbers?

Generate 1 to 100,000 numbers at once.

Decimal Places

Number of decimal places (only for decimal mode).

Methodology

Formula:: Random value in range
Content last updated:: August 2026
Scheduled re-verification:: August 2027

Calculation type: Exact calculation.

Formula & methodology

Formula used

Random value in range

value = min + random × (max − min)

A uniform draw across the range, so every value between the bounds is equally likely.

Integers

value = ⌊min + random × (max − min + 1)⌋

Includes both endpoints when integer-only mode is on.

Without duplicates

draw and discard repeats until the requested count is filled

This requires the range to hold at least as many distinct values as the count requested.

Variable definitions

Symbol	Meaning	Unit
min	Minimum. the lower bound, inclusive	number
max	Maximum. the upper bound, inclusive for integers	number
count	How many. the quantity of numbers to generate	count

Step-by-step calculation

1. Set the range and how many numbers you want
The maximum must be at least the minimum.
2. Choose integers or decimals, and whether repeats are allowed
Unique draws need a range wide enough to supply them.

Limitations

Suitable for games, sampling, draws and testing. Not appropriate for cryptography, lotteries or anything where the numbers carry real value.
Numbers are generated fresh in your browser each time and are never stored, so a result cannot be reproduced or audited afterwards.
Requesting more unique values than the range contains is impossible and is rejected.

This page is educational. It applies the formula described above to the figures you enter and shows the arithmetic behind the result. The output is only as good as the inputs and the assumptions listed here, and it is general information rather than advice about your particular situation.

Help & FAQs

Frequently Asked Questions

Clear answers to common questions to help you use this calculator confidently.

How do I generate a random number between two values?

Tap to view the answer

Enter your minimum and maximum values, set count to 1, and click Generate. The tool instantly produces a random number within your range.

How do I get unique random numbers without repeats?

Tap to view the answer

Uncheck 'Allow Duplicates.' The generator ensures all values are distinct — ideal for lottery picks or selecting unique samples.

Can I generate decimal random numbers?

Tap to view the answer

Yes. Uncheck 'Generate Integers Only' and set your desired decimal precision. The generator produces decimal values within your range.

How many numbers can I generate at once?

Tap to view the answer

Up to 100,000 numbers in a single generation. Enter your desired count and all values are produced instantly.

What's the difference between pseudorandom and true random?

Tap to view the answer

True randomness comes from physical processes (like radioactive decay). Pseudorandom numbers, like those from this tool, use algorithms seeded with entropy and are sufficient for virtually all practical applications.

Need more help? Contact support or email globalcalqulate@gmail.com

We typically reply within 24–48 hours.

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How to Use This Calculator

Set Your Range

Enter the minimum and maximum values for your random numbers.

Choose Count

Specify how many numbers you need — from 1 to 100,000.

Select Options

Choose integer or decimal, allow or forbid duplicates, and optionally sort results.

Generate

Results appear instantly. Click 'Regenerate' for a fresh set of numbers.

Understanding Your Results

Pseudorandom Numbers
This generator uses the Web Crypto API when available for cryptographic-quality randomness, falling back to Math.random() for broader compatibility. Numbers are pseudorandom — they appear random but are generated by a deterministic algorithm seeded with high-entropy values.
Inclusive vs Exclusive Ranges
For integers, the maximum value is inclusive (e.g., min=1, max=10 can produce 10). For decimals, the maximum is exclusive (e.g., min=1, max=10 produces values < 10).
Unique Values
When 'Allow Duplicates' is off, the generator ensures all numbers are distinct. This requires enough range to accommodate the count — for integers, you need at least as many values in the range as the count requested.

Key Tips

✓
For dice rolls, set min=1, max=6, count=1, integers only, with duplicates allowed.
✓
For lottery-style picks, disable duplicates and set your desired range (e.g., 1-49).
✓
For randomized test data, generate large batches with count=1,000+ to populate test databases.
✓
For sampling or A/B testing, generate numbers and assign them to users or variations.

Understanding Random Number Generation

What Are Random Numbers?

A random number is a value selected unpredictably from a specified range. True randomness requires physical processes (radioactive decay, thermal noise), while computers generate pseudorandom numbers — sequences that appear random but are produced by deterministic algorithms. For most practical purposes — games, simulations, sampling, cryptography — pseudorandom numbers are sufficient when generated from high-quality entropy sources like the Web Crypto API.

Integer vs Decimal Random Numbers

Integer random numbers are whole numbers within a range. They're ideal for dice rolls, lottery picks, random sampling from a list, or generating IDs. Decimal random numbers include fractional values and are better for simulations, coordinate generation, or any scenario requiring continuous values. The generator lets you specify decimal precision from 0 to 10 places.

With vs Without Duplicates

Allowing duplicates means each number is generated independently — the same value can appear multiple times. This reflects true independence, like rolling a die where landing on 6 doesn't prevent future 6s. Disallowing duplicates ensures unique values, useful for selecting distinct items (e.g., picking 5 unique winners from a pool) or shuffling. Note that unique generation requires sufficient range — you can't pick 10 unique integers between 1 and 5.

Use Cases for Random Number Generators

Random numbers power many real-world applications: cryptography (encryption keys, nonces), gaming (dice, card shuffles, loot drops), scientific computing (Monte Carlo simulations, randomized controlled trials), machine learning (weight initialization, data shuffling), A/B testing (group assignment), and lottery/sweepstakes (fair selection). Our generator serves all these use cases with configurable range, count, and uniqueness settings.

Formula & methodology

Formula used

Random value in range

value = min + random × (max − min)

A uniform draw across the range, so every value between the bounds is equally likely.

Integers

value = ⌊min + random × (max − min + 1)⌋

Includes both endpoints when integer-only mode is on.

Without duplicates

draw and discard repeats until the requested count is filled

This requires the range to hold at least as many distinct values as the count requested.

Variable definitions

Symbol	Meaning	Unit
min	Minimum. the lower bound, inclusive	number
max	Maximum. the upper bound, inclusive for integers	number
count	How many. the quantity of numbers to generate	count

Step-by-step calculation

1. Set the range and how many numbers you want
The maximum must be at least the minimum.
2. Choose integers or decimals, and whether repeats are allowed
Unique draws need a range wide enough to supply them.

Limitations

Suitable for games, sampling, draws and testing. Not appropriate for cryptography, lotteries or anything where the numbers carry real value.
Numbers are generated fresh in your browser each time and are never stored, so a result cannot be reproduced or audited afterwards.
Requesting more unique values than the range contains is impossible and is rejected.

Calculator inputs

Range Settings

Generation Options

Your results

Methodology

Formula & methodology

Formula used

Random value in range

Integers

Without duplicates

Variable definitions

Step-by-step calculation

Limitations

How do I generate a random number between two values?

How do I get unique random numbers without repeats?

Can I generate decimal random numbers?

How many numbers can I generate at once?

What's the difference between pseudorandom and true random?

Related calculators

More everyday calculators

Calculator inputs

Range Settings

Generation Options

Your results

Methodology

How to Use This Calculator

Example: Rolling Five Dice

Understanding Your Results

Key Tips

Understanding Random Number Generation

What Are Random Numbers?

Integer vs Decimal Random Numbers

With vs Without Duplicates

Use Cases for Random Number Generators

Formula & methodology

Formula used

Random value in range

Integers

Without duplicates

Variable definitions

Step-by-step calculation

Limitations

How to Use This Calculator

Example: Rolling Five Dice

Understanding Your Results

Key Tips

Understanding Random Number Generation

What Are Random Numbers?

Integer vs Decimal Random Numbers

With vs Without Duplicates

Use Cases for Random Number Generators