About this tool
Type a number in any field — decimal, hexadecimal, binary, octal or a base of your choice up to 36 — and every other field updates as you type. It accepts the 0x, 0b and 0o prefixes, a minus sign and _ or spaces between digits, and works with whole numbers of any size, far beyond 64 bits. The results show the binary grouped in nibbles, hexadecimal in bytes and decimal with thousands separators, each one click to copy. For negative numbers it shows the two’s complement pattern at 8, 16, 32 or 64 bits — the way computers store them — plus the big-endian bytes and what the same bits mean when read as signed. Useful for programming, networks, colour codes and computer science classes.
How to use it
- 1 Type the number in the field of its base (decimal, hex, binary, octal or another base).
- 2 Read the same value in every other base.
- 3 For negative numbers, choose 8, 16, 32 or 64 bits to see the two’s complement.
- 4 Click any result to copy it.
Frequently asked questions
How do you convert binary to decimal by hand?
Multiply each digit by 2 raised to its position, counting from 0 on the right, and add: 1101 = 1×8 + 1×4 + 0×2 + 1×1 = 13. To go from decimal to binary, divide by 2 repeatedly and read the remainders from the last to the first.
Why does −1 become 11111111?
Computers store negative integers in two’s complement: invert the bits of the positive value and add 1. In 8 bits, 1 is 00000001; inverted it is 11111110, plus 1 gives 11111111. The same bits read as unsigned are 255.
Is there a size limit?
The tool uses arbitrary-precision integers (BigInt), so numbers far larger than 64 bits convert exactly, up to 2,000 digits. Fractions are not supported: only whole numbers.
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