Binary to Decimal Converter

Convert between binary and decimal number systems.

Bidirectional

Convert binary to decimal or decimal to binary.

All Bases

Also shows octal and hexadecimal representations.

Step by Step

See the positional notation breakdown.

FAQ

How to convert binary to decimal?

Multiply each digit by 2^position (right to left, starting at 0) and sum. E.g., 1010 = 1×8 + 0×4 + 1×2 + 0×1 = 10.

How to convert decimal to binary?

Repeatedly divide by 2 and read remainders bottom-up. E.g., 10 ÷ 2 = 5r0, 5÷2 = 2r1, 2÷2 = 1r0, 1÷2 = 0r1 → 1010.