Number Base Converter
Convert numbers between any base from 2 to 36, including binary, octal, decimal, and hexadecimal. Supports arbitrarily large numbers and negative values.
Quick Presets
Recommended Settings
Pro Tips
- •Any base from 2 to 36 is supported, using digits 0-9 and letters a-z for values above 9
- •Very large numbers are handled precisely using arbitrary-precision arithmetic (no floating-point rounding)
- •Negative numbers are supported with a leading minus sign
- •The Quick Reference panel always shows the same value in binary, octal, decimal, and hex at once
- •Use the swap button to flip the From/To bases and reuse the current result as the new input
Most Popular
Most conversions are decimal to binary or hexadecimal to decimal for programming and debugging
When to Use This Tool
Convert values between decimal, hexadecimal, octal, and binary when working with bit flags, memory addresses, color codes, or file permissions.
Learn and teach how positional number systems work by converting the same value across binary, octal, decimal, and hexadecimal side by side.
Convert register values, opcodes, or signal states between bases when designing or debugging digital circuits and embedded systems.
Convert to or from less common bases, like base 36 or base 20, for encoding schemes, custom identifiers, or puzzle and cryptography exercises.
How It Works
Enter the number you want to convert and set its current base (From Base)
Set the base you want to convert it to (To Base)
The input is parsed digit by digit using arbitrary-precision arithmetic, so very large numbers convert exactly
The parsed value is then repeatedly divided by the target base to produce each output digit
The result updates live as you type, along with a quick-reference table in binary, octal, decimal, and hex
100% Private
Files never leave your device. All processing happens locally in your browser.
Lightning Fast
Powered by Pure JavaScript (BigInt) for optimal performance on modern browsers.
Secure
No data collection, no tracking, no sign-up required.
Frequently Asked Questions
What bases are supported?
Any base from 2 to 36. Digits above 9 use letters a through z, so base 16 (hexadecimal) uses 0-9 and a-f, and base 36 uses the full 0-9 and a-z alphabet.
Can I convert very large numbers?
Yes. The tool uses JavaScript's BigInt for arbitrary-precision arithmetic, so it converts numbers of any size exactly, without the rounding errors that regular floating-point math would introduce.
Are negative numbers supported?
Yes. Enter a leading minus sign (e.g. -101) and the converted result will also include a minus sign in the target base.
What does the 'Uppercase letters' option do?
For bases above 10, digits above 9 are represented with letters. This option controls whether those letters appear as uppercase (FF) or lowercase (ff) in the output.
What is the Quick Reference table for?
It shows your input value converted to the four most common bases - binary, octal, decimal, and hexadecimal - all at once, regardless of what To Base you've selected.