Number Base Converter
Convert between binary, octal, decimal, and hexadecimal.
Usage examples
Turning a hex color code or memory address into decimal
Type a hex value you ran into while programming or debugging and instantly see it in decimal, or go the other way from decimal to hex.
Checking the raw bit pattern of a number
See exactly how a decimal or hex number is represented in binary, and which bits are set.
Understanding Unix file permission notation (octal)
Convert an octal permission value like chmod 755 to decimal or binary to see what each digit actually grants.
Frequently asked questions
Is the value I enter sent to a server?
No. All conversions happen entirely in your browser, and the value you enter is never sent to a server.
Does it stay accurate for very large numbers?
Yes. Unlike ordinary floating-point math, the conversion uses a lossless arbitrary-precision representation, so even very large numbers convert exactly.
Can I enter negative numbers?
No. Negative numbers are represented differently across bases (such as two's complement), which would be confusing, so only non-negative integers are supported.
Can I convert decimal values with a fractional part?
No. Only whole numbers are supported — you can't enter a decimal point.