💻 Developer Tools

Number Base Converter

Convert numbers between binary, octal, decimal and hexadecimal. Edit any one field and the others update on the spot. Any base from 2 to 36 works too, and big integers are handled accurately with BigInt. Everything stays in your browser.

Type an integer in any field and the rest convert automatically. Hex accepts both upper- and lowercase.

Examples (click to try)

Paste a prefixed value like 0xFF / 0b1010 / 0o755 and the base is detected automatically.

Pick any base from 2 to 36. Digits use 0-9 and a-z.

How to Use the Number Base Converter

Enter an integer into any of the binary, octal, decimal or hexadecimal fields, and the rest convert instantly. Use the button beside each field to copy that value.

  • Start from any field: whichever field you edit becomes the source, and the other three fields plus the custom-base field update live.
  • Hex is case-insensitive: FF and ff are treated as the same value.
  • Custom base (2–36): choose a base in the dropdown and type a value on the left to convert both ways. Digits use 0-9 and a-z.
  • Big integers supported: conversions run on BigInt, so huge integers beyond 64 bits convert without rounding errors.

For example, type 255 in the decimal field and it becomes 11111111 in binary, 377 in octal and FF in hex on the spot. Paste a prefixed value copied from code — such as 0xFF, 0b1010 or 0o755 — into any field and the base is detected automatically.

Where This Comes in Handy

  • Checking color codes (#ff8800) or bitmasks between hex and decimal
  • Reading network subnets or permissions (octal, like chmod 755)
  • Translating memory addresses or register values between binary and hex
  • Working with unusual bases such as base 32 or base 36 in puzzles and assignments

Frequently Asked Questions

Is the number I enter sent to a server?
No. All conversions run entirely in your browser. The numbers you enter are never transmitted to or stored on any server, so you can use the tool with confidence.
Can it convert very large numbers accurately?
Yes. It uses JavaScript BigInt internally, so integers with many digits convert without rounding errors — even values beyond the usual 64-bit range.
What is the custom base, and why 2 to 36?
The custom field lets you pick any base (radix) you like. Digits use 0-9 followed by a-z, which gives 36 possible symbols — so the highest base you can represent is 36, including bases like 32 or 36.