Binary to Decimal Converter

Binary numbers use only 0 and 1. To convert to decimal, multiply each binary digit by its positional power of 2 and sum the results. This converter does that instantly for any length binary string, including 8-bit bytes, 16-bit words, and 32-bit integers.

Step-by-step guide

1. Enter the binary number: Type your binary digits (e.g. 11111111) in the Input field — only 0s and 1s are valid.
2. Select Binary as the input base: Choose Binary (base 2) from the From base selector.
3. Read the decimal result: The Decimal output shows the converted value — for 11111111 that is 255.
4. Check the bit length: The Bit length field tells you how many bits are needed to represent the value — useful for choosing the right integer type.

Frequently asked questions

How do I manually convert binary 1010 to decimal?

Write out each bit position from right: 0×2^0 + 1×2^1 + 0×2^2 + 1×2^3 = 0 + 2 + 0 + 8 = 10. The converter handles this arithmetic for any length automatically.

What is the decimal value of the binary byte 10000000?

128. It is 2^7, the highest bit in an 8-bit byte. The tool also reports this as a power of two.

Can I convert negative binary numbers?

This tool converts unsigned binary integers. For two's complement negative numbers, the interpretation depends on the word width — a convention the tool does not assume.