🔒 Runs in your browser — nothing is uploaded✓ Free, no signup
Number Base Converter
Type a number in binary, octal, decimal, hexadecimal or any base up to 36 and see it in every other base instantly — even numbers far larger than 64 bits.
Type in any box — the others update instantly. Works with numbers of any size.
When should you use the Number Base Converter?
- Converting hex colour, memory or error codes to decimal
- Checking binary flags and bit masks
- Learning or teaching how number bases work
How to use the Number Base Converter
- 1
Type in any box
Enter a value in binary, octal, decimal or hex. The other boxes update as you type.
- 2
Use prefixes if you like
0x, 0b and 0o prefixes, spaces, commas and underscores are ignored.
- 3
Try another base
Pick any base from 2 to 36 in Custom base.
- 4
Copy
Copy the value you need. Tick 'Group digits' for easier reading.
Examples
255 in every base
Decimal
255
Converted
Binary 11111111 Octal 377 Hexadecimal FF Base 36 73
Common errors and how to fix them
"G" is not a valid base-16 digit- Each base only allows certain digits — hex uses 0–9 and A–F. Check you typed in the right box.
Negative numbers in binary- Negative values are shown with a minus sign, not two's complement. For two's complement, add 2^n to the negative number first.
More from Encoding & Security
Free tools that run in your browser — no signup, nothing uploaded.
JWT Decoder
Decode and inspect JSON Web Tokens (JWT) Header and Payload.
JWT Generator
Create and sign HS256/HS384/HS512 JSON Web Tokens for testing.
Hash Generator (MD5, SHA)
Generate MD5, SHA-1, SHA-256, SHA-384 and SHA-512 hashes.
Password Generator
Generate strong, random passwords with the length and characters you choose.
Base64 Encoder ⇆ Decoder
Encode text to Base64 and decode Base64 to text for API debugging.
URL Encoder & Decoder
Cleanly encode special characters in URLs and decode query strings.
String Escape & Unescape
Escape or unescape strings for JavaScript, Java, C#, HTML, XML, SQL, CSV and regex.
HTML Entity Encoder & Decoder
Encode special characters as HTML entities, or decode entities back to text.
Text to Hex & Binary Converter
Convert text to hex, binary, ASCII codes or Unicode code points — and back.
Number Base Converter FAQ
Type the binary number in the Binary box and read the result in the Decimal box. Each binary digit is a power of 2: 1010 = 8 + 0 + 2 + 0 = 10.
Type the number in the Decimal box. Hexadecimal uses digits 0–9 and A–F, so 255 becomes FF.
There's no practical limit. The converter uses arbitrary-precision integers, so numbers with hundreds of digits convert exactly.
Base 36 uses the digits 0–9 and the letters A–Z. It's sometimes used for short IDs, because large numbers become compact strings.
No — it converts whole numbers (integers), which is what base conversion is usually needed for.
No. All conversions happen in your browser.