Binary to Decimal Converter

Convert binary ↔ decimal with powers of 2. Example: 11111111 → 255.

BinaryDecimal
101010
111115
11111111255

By hand

Write place values under each bit (128 64 32 16 8 4 2 1) and add where the bit is 1.

FAQ

How do I convert binary to decimal?

Add powers of 2 for every bit that is 1.

What is 1010 in decimal?

8+2 = 10.

Related: Binary to Hex, Powers of 2 guide.

Full interactive tool loads with JavaScript. Canonical page.