Binary to Decimal Converter
Convert binary to decimal instantly (101010 → 42), with the working shown step by step, every other base at once, negative numbers and two’s complement, a clickable bit grid and a list mode.
- Your data never leaves your device
- 100% free
- No sign-up
- Works offline after first load
How to use the binary to decimal converter
- Type or paste the number (prefixes, spaces and underscores are fine).
- Pick the bases — the result, the other bases, the bits and the working appear instantly.
- Swap, choose signed / bit width / grouping, convert a list, or copy and share.
About Binary to Decimal
Convert binary to decimal as you type. The answer comes with the working shown step by step, so you can check it or learn the method.
The same number is shown in every common base, as big- and little-endian bytes and as bits you can click to flip. Choose signed two’s complement and a bit width, group digits, pad with zeros, add 0x / 0b prefixes, convert a whole list at once or inspect how a float is stored in IEEE-754.
Good for
- Programming, debugging and reading memory dumps
- Computer science and digital electronics homework
- Networking masks, colours, permissions and flags
Tip: Click the bits in the grid to flip them — the number updates in every base, which is a quick way to build masks and flags.
Frequently asked questions
How do I convert binary to decimal?
Multiply each bit by its power of 2 (1, 2, 4, 8, … from the right) and add them: 101010 = 32 + 8 + 2 = 42.
Can it convert negative numbers?
Yes. Type a minus sign for a signed value, or choose “Signed (two’s complement)” and a bit width (8, 16, 32, 64 or 128) to see how a computer stores it — for example −5 in 8 bits is 11111011.
Is there a size limit?
No practical limit — it uses arbitrary-precision integers, so 64-bit, 128-bit and even longer numbers convert exactly, with no rounding.
Can it convert fractions?
Yes — use a point (e.g. 101.101). Repeating digits are marked, and you can choose how many fraction digits to show.
Can I convert many numbers at once?
Yes — choose “Convert a list”, paste one number per line and copy all the results.
What are some common binary to decimal values?
1010 → 10, 11111111 → 255, 101010 → 42 and 10000000 → 128.