Number Base Converter

Converts a number entered in any one of four bases — binary (base 2), octal (base 8), decimal (base 10), or hexadecimal (base 16) — into the other three simultaneously, so you never have to convert one pair at a time.

Type a number into any one of the four input fields; the tool detects which base you're using from which field you typed in and fills in the other three fields automatically.

Entering `255` in the decimal field fills in `11111111` for binary, `377` for octal, and `FF` for hexadecimal — the same quantity, just written in four different positional number systems.

Each system represents the same value using a different number of digits per position: binary uses only 0 and 1, octal uses 0–7, decimal uses 0–9, and hexadecimal extends past 9 with the letters A–F to represent 10 through 15, which is why `FF` in hex equals `255` in decimal.

Negative values are converted correctly and shown with a leading minus sign in every base; entering digits invalid for the selected base — like a `2` in a binary field or a `G` in hex — is rejected or ignored rather than producing an incorrect result.

Base conversion is common when reading memory addresses, color codes, file permissions, IP subnet masks, or bitwise flags in source code, where the same number is often written in hex or octal for compactness even though it's stored as a decimal value at runtime.

Conversion runs entirely in your browser via client-side JavaScript; the numbers you enter are never uploaded to a server or stored.