What is Random Number Generator?

Random Number Generator is a versatile tool for generating random numbers in three modes: Integer, Decimal, and Percentage. Whether you need a single random number or hundreds at once, this tool provides cryptographically strong randomness with flexible customization options.

Why Use This Tool?

Random numbers are essential in many situations: picking winners for contests, making fair decisions, creating test data, running simulations, or simply settling a debate. This tool goes beyond basic random generation by offering advanced controls like step intervals, odd/even filtering, number exclusion, and duplicate prevention.

Three Modes for Every Need

Integer Mode

Generate whole numbers within a range. Ideal for dice rolls, lottery picks, team assignments, and any scenario requiring discrete values.

Decimal Mode

Generate numbers with configurable decimal places (0-10). Useful for statistical sampling, scientific experiments, and financial modeling.

Percentage Mode

Generate random percentages within a range. Results include the % symbol for easy reading and copying.

Who Is This For?

Teachers

Generating random numbers for classroom activities and quizzes

Gamers

Needing dice rolls or random selections for board games and RPGs

Developers

Creating test data with specific constraints

Researchers

Performing random sampling for surveys and experiments

Anyone

Needing a quick, fair, and unbiased random number

Your Data Stays Private: All number generation happens in your browser using the Web Crypto API. No server requests, no tracking, and history stored locally on your device only.

Table of Contents

1. What is Random Number Generator?
2. How to Use Random Number Generator
3. Features
4. Frequently Asked Questions

How to Use Random Number Generator

Basic Usage

Choose a mode

Select Integer, Decimal, or Percentage from the tabs at the top

Set your range

Enter minimum and maximum values, or click a Quick Preset button

Click Generate

A random number appears with a rolling animation

Copy your result

Click the Copy button to copy the number to your clipboard

Using Quick Presets

Each mode has preset range buttons for common scenarios. Click any preset to instantly set the Min and Max values:

Integer Presets

1-6 - Standard dice roll
1-10 - Rating scale
1-100 - Common range
1-1000 - Large pool

Decimal Presets

0-1 - Probability values
0-10 - Rating with decimals
0-100 - Standard range
-1 to 1 - Normalized values

Percentage Presets

0-100% - Full percentage range
0-50% - Lower half
50-100% - Upper half
0-1000‰ - Per mille (parts per thousand)

Advanced Options

Click the Options button to reveal additional controls for customizing your random number generation:

Quantity

Generate up to 1,000 numbers at once. Multiple results display as badges with automatic statistics (Sum, Average, Min, Max) calculated below.

Decimals

Set decimal places (0-10) for Decimal and Percentage modes. Control precision for scientific calculations or financial modeling.

Step

Set increment intervals in Integer mode (e.g., step 5 produces 5, 10, 15, 20...). Perfect for generating multiples or specific intervals.

Sort

Sort results in ascending or descending order, or leave them in random sequence. Works across all three modes.

Filter (Odd/Even)

Restrict to odd or even numbers only in Integer mode. Useful for specific mathematical requirements or game rules.

Exclude Numbers

Enter specific numbers to exclude from results in Integer mode (e.g., "13, 7, 42"). Those numbers will never appear in your generated results.

No Duplicates

Ensure all generated numbers are unique in Integer mode using Fisher-Yates shuffle algorithm. Perfect for lottery picks or unique ID generation.

Auto Generate

Enable automatic generation at a configurable interval (1-60 seconds). The Generate button turns green to indicate auto mode is active.

Viewing Multiple Results

When generating more than one number, the tool provides enhanced visualization and statistics:

Results appear as individual badges in a responsive grid layout
Statistics are shown below: Sum, Average, Min, and Max
Click Copy to copy all numbers as a comma-separated list

Using History

Every generation is automatically saved to your history for easy reference and reuse:

View Past Results

See timestamp, mode, range, and generated numbers for each entry

Quick Reload

Click any history entry to reload its settings (mode, min, max, quantity)

Persistent Storage

History persists across browser sessions via local storage

Easy Management

Click Clear to remove all history entries when needed

Pro Tips: Press Enter in any input field to quickly generate without clicking the button. Use Auto generate for continuous random number streams. Combine options to create complex scenarios like generating 10 unique odd numbers between 1-100 sorted ascending.

Features

Three Generation Modes

Switch between modes instantly using the tab interface:

Integer

Whole Numbers

Full control over step intervals
Odd/even filtering
Number exclusion
Uniqueness guarantee

Decimal & Percentage

Floating-Point

Configurable decimal places (0-10)
Scientific precision
Automatic % formatting
Positive and negative ranges

Customizable Range

Set any minimum and maximum value for your random numbers. Each mode includes Quick Preset buttons for commonly used ranges, and the range accepts both positive and negative values.

Batch Generation

Generate up to 1,000 numbers in a single click. Multiple results are displayed as a badge grid with automatic statistics (Sum, Average, Min, Max) calculated below.

Integer-Specific Controls

When using Integer mode, additional options are available:

Step Intervals

Generate numbers at specific intervals (e.g., multiples of 5)

Odd/Even Filter

Restrict results to odd or even numbers only

Exclude Numbers

Enter specific numbers to remove from the pool

No Duplicates

Ensure every generated number is unique using Fisher-Yates shuffle

Sorting Options

Results can be sorted in ascending or descending order, or left in their random sequence. Sorting works across all three modes.

Auto Generate

Enable automatic generation to produce new random numbers at a regular interval. Set the timer between 1 and 60 seconds. The Generate button changes color to indicate auto mode is active.

Cryptographic Randomness

Enterprise-Grade Security: Unlike basic random generators that use Math.random(), this tool uses the Web Crypto API (crypto.getRandomValues()) for stronger, more unpredictable randomness. This is the same technology used in security applications.

Rolling Animation

When generating a single number, a brief rolling animation displays rapidly changing numbers before revealing the final result. This adds a tactile feel similar to rolling physical dice.

One-Click Copy

Copy results to your clipboard instantly. Single numbers copy as-is, while multiple numbers copy as a comma-separated list. Percentage results include the % symbol.

Generation History

All generations are automatically saved to history (up to 1,000 entries):

View timestamps, modes, ranges, and results at a glance
Click any entry to reload its settings for quick re-generation
Data persists in local storage across browser sessions
Clear history with one click when needed

Responsive Design

The tool adapts seamlessly to any screen size:

Desktop

Full layout with all options visible

Tablet

Optimized grid for medium screens

Mobile

Compact layout with touch-friendly controls

Frequently Asked Questions

How random are the generated numbers?

This tool uses crypto.getRandomValues(), which is a cryptographically secure random number generator built into your browser. It provides significantly stronger randomness than the standard Math.random() function, making it suitable for contests, games, and any scenario where fairness matters.

Security Note: The Web Crypto API is the same technology used in security applications, providing unpredictable and unbiased results.

What is the maximum range I can use?

You can enter any numeric value for Min and Max. However, in Integer mode, if the total number of possible values in the pool exceeds 1,000,000 (for example, a range of 1 to 10,000,000 with step 1), a warning will appear and no numbers will be generated. This limit prevents browser freezing.

Note: For Decimal and Percentage modes, there is no pool size limit.

Can I generate numbers without duplicates?

Yes, enable the No duplicates toggle in the Options panel (available in Integer mode). The tool uses a Fisher-Yates shuffle algorithm to efficiently select unique random numbers.

Important: If you request more unique numbers than exist in the pool, it will return as many as possible.

What does the Step option do?

Step controls the increment between possible values. For example, with Min=0, Max=100, and Step=10, the possible results are 0, 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100. This is useful for generating multiples or specific intervals.

Example use cases:

Generate multiples of 5 for pricing tiers
Create even-spaced intervals for data sampling
Simulate dice with custom faces (e.g., 2, 4, 6, 8, 10)

How does the Exclude feature work?

Enter comma-separated numbers in the Exclude field (e.g., "13, 7, 42"), and those numbers will never appear in results. This is available in Integer mode only. Non-numeric entries are silently ignored.

Practical examples:

Exclude unlucky numbers for superstitious users
Remove already-used values in sequential draws
Skip specific IDs that are reserved or invalid

What is Auto Generate?

Auto Generate continuously produces new random numbers at a set interval. Open the Options panel, enable the Auto generate toggle, and set the interval (1-60 seconds). The Generate button turns green to indicate auto mode is active.

Features:

Skips rolling animation for faster results
Stops automatically when you switch modes or toggle it off
Perfect for live displays or continuous monitoring

What is the difference between Integer, Decimal, and Percentage modes?

Feature	Integer	Decimal	Percentage
Number Type	Whole numbers	Floating-point	Floating-point with %
Step Control	Yes	No	No
Odd/Even Filter	Yes	No	No
Exclude Numbers	Yes	No	No
No Duplicates	Yes	No	No
Decimal Places	N/A	0-10	0-10

Is my generation history saved?

Yes, up to 1,000 recent generations are stored in your browser's local storage. History persists across sessions and includes the mode, range, quantity, and results. Click any history entry to reload those settings. Click Clear to delete all history.

Privacy Note: History is stored only on your device and never transmitted to any server.

Can I use this tool offline?

After the initial page load, the tool works completely offline. All random number generation happens locally in your browser with no server communication required.

Offline Capability 100%

Is my data private?

Yes. All processing occurs entirely in your browser. No data is sent to any server. Your generation history is stored only in your browser's local storage and is never transmitted externally.

No Server Requests

All generation happens locally

No Tracking

Zero usage data collection

Local Storage Only

History stays on your device