Binary to Decimal

How Binary to Decimal works

Convert binary numbers to decimal, hexadecimal and octal, with invalid digits flagged. Everything happens inside this page: the tool reads your input, runs the calculation or conversion locally, and hands the result back to you. Nothing is transmitted, because there is no backend to transmit it to.

That design choice is deliberate. Most free tool sites upload your files to a server, process them there, and quietly keep a copy. Toolcin cannot do that — the site is a set of static files. If your connection dropped the moment the page finished loading, every tool would still work.

Positional value, one bit at a time

Binary is base 2, so each position is worth a power of two: 1, 2, 4, 8, 16 and so on from the right. 11001010 is 128 + 64 + 8 + 2 = 202.

The tool also prints the hexadecimal and octal forms, because those are the representations you actually use when reading a memory dump or a colour value. Hex groups four bits, octal groups three, which is why they convert so cleanly from binary.

Input rules

Only 0 and 1 are accepted; any other character produces an error rather than a silently wrong number. Spaces are stripped, so a grouped value such as 1100 1010 converts without you having to retype it.

Leading zeros do not change the value, but they do change the width. If a field expects a fixed 8-bit value, keep the zeros — 00000101 is 5 either way, but 101 may be read as three bits by whatever is consuming it.

Eight bits is a byte, not a rule

Binary numbers have no fixed length. Eight bits is the convention for a byte, but 11001010 and 0011001010 are different numbers and both are valid input. The confusion usually comes from fixed-width contexts like IP octets or colour channels, where the field really is eight bits and a shorter input is padded on the left.

Negative numbers are not handled here — two's complement has no minus sign in binary, and interpreting the top bit as a sign is a decision that depends on the width you assume.

Good to know

• Works offline once loaded, including on flights and in locked-down networks.
• No file size limit beyond your device's own memory.
• Free to use, with no account and no usage counter.
• Results are produced locally, so they are not logged or shared with anyone.

Questions