Developer tools
Number base converter
Type a whole number in any base and the others update instantly, with arbitrary precision. Everything runs in your browser - nothing is uploaded.
How it works
Type a number in any base - binary, octal, decimal, or hexadecimal - and the others update instantly. Binary uses only 0 and 1, octal uses 0 to 7, decimal is the everyday base 10, and hexadecimal uses 0 to 9 plus a to f to pack four binary digits into one symbol. Converting between them is a common task when reading memory dumps, color codes, file permissions, or other low-level data.
The conversion uses arbitrary-precision integers, so even very long hexadecimal or binary values convert exactly without rounding. Enter a value in one field and the rest follow; clear it and they reset. Everything runs in your browser, and digits that are invalid for the chosen base are flagged rather than silently dropped.
Example. Decimal 255 is 11111111 in binary, 377 in octal, and ff in hexadecimal. That is also why white is #ffffff in CSS: three color channels, each maxed out at 255.
FAQ
How do I convert decimal to binary?
Repeatedly divide the number by 2 and read the remainders from bottom to top, or just type the decimal value here and read the binary result. For example 255 is 11111111, and 256 rolls over to 100000000.
How does hexadecimal work?
Hexadecimal is base 16, using 0 to 9 then a to f for the values 10 to 15. Each hex digit maps to exactly four binary digits, which makes it a compact way to write binary: ff is 11111111, and 10 in hex is 16 in decimal.
Can it handle very large numbers?
Yes. The tool uses arbitrary-precision integers, so large binary or hexadecimal values convert exactly, with no loss from floating-point rounding. It works with whole numbers; fractional values are not supported.
Is anything sent to a server?
No. The conversion runs entirely in your browser as simple integer math. Nothing you type is uploaded, logged, or stored.