Convert numbers between binary, octal, decimal, and hexadecimal instantly. Powered by BigInt for large values.
Programmers working with bitmasks, colour codes, and low-level data.
Type in any base
Enter a value into the binary, octal, decimal, or hexadecimal field.
See all bases
The other three fields update instantly with the equivalent value.
Copy a value
Click the copy icon next to the base you need.
Binary, octal, decimal, and hexadecimal are just different ways of writing the same number, and low-level programming moves between them constantly — reading a hex memory address, setting binary bitmask flags, interpreting a byte value, or matching a colour channel. Converting in your head is slow and a single misplaced digit gives a silently wrong result, which is a nasty bug to chase. This converter shows a value in all four bases at once: type into any field — binary, octal, decimal, or hex — and the other three update instantly. It uses JavaScript BigInt under the hood, so even very large values stay exact rather than losing precision the way ordinary numbers do beyond a certain size. Everything runs in your browser, and you can copy whichever representation you need with one click.
Bitmasks & flags
Convert binary flag combinations to hex and decimal while writing or reading code.
Colour & byte work
Translate hex colour channels or byte values into decimal and binary.
Memory & addresses
Read hexadecimal addresses and offsets as decimal when debugging.
Networking
Convert values between bases when working with masks, ports, and protocol fields.
Learning CS
See exactly how one number is represented across number systems to understand place value.
It uses JavaScript BigInt, so it stays exact for numbers far beyond the usual 64-bit limit where normal numbers lose precision.
Binary is base-2 (0–1), octal base-8 (0–7), decimal base-10, and hexadecimal base-16 (0–9, a–f). Each is a compact way of writing the same value.
It is designed for non-negative whole numbers across the four bases.
No — it converts whole numbers (integers) between bases.
No. You can enter hex digits in upper or lower case; a–f and A–F are treated the same.
Two hex digits map exactly to one byte (0–255), so hex is a tidy, readable shorthand for binary data and colour channels.
No. It runs entirely in your browser.
Yes — convert as many values as you like for free, with no sign-up.