Type a binary number and its decimal and hexadecimal values appear instantly. Each binary digit is a power of two, added up from right to left.
How to use the binary to decimal converter
- Type the binary number, for example 101010.
- Read the decimal result: 42.
How to convert binary to decimal by hand
Write the powers of two under each digit from the right: 1, 2, 4, 8, 16, 32… Add the powers where the digit is 1. For 101010: 32 + 8 + 2 = 42.
Frequently asked questions
What is 11111111 in decimal?
255, the largest value of one byte.
Updated October 2026 · Built and tested by Sharjeel Tahir · How our tools are tested