Binary to Decimal Converter
Binary represents numbers using only 0 and 1, where each position is a power of two. Converting to decimal means summing the place values for every 1 bit — the rightmost bit is 1, the next is 2, then 4, 8, and so on.
Type a binary string below and its decimal value appears instantly. The tool validates that you have entered only 0s and 1s, and the conversion happens entirely in your browser with no upload.
| Binary | Expansion | Decimal |
|---|---|---|
1 | 1 | 1 |
10 | 2 | 2 |
1010 | 8 + 2 | 10 |
1111 | 8 + 4 + 2 + 1 | 15 |
10000000 | 128 | 128 |
1010→10Bits set at positions 8 and 2 sum to 10.
Frequently asked questions
How do I convert binary to decimal manually?
Write the power of two above each bit (1, 2, 4, 8, … from right to left), then add the powers wherever the bit is 1. For 1010 that is 8 + 2 = 10.
What characters are allowed in binary input?
Only the digits 0 and 1. Spaces are ignored for grouping, but any other character makes the input invalid and the converter will flag it.
How large a binary number can this handle?
It comfortably handles the full range of standard 64-bit integers. Extremely long bit strings beyond that range may lose precision, as with any double-precision arithmetic.
Is the conversion done privately?
Yes. It runs locally in your browser; nothing you type is sent to a server.