Binary to Decimal Converter

Convert binary to decimal, hexadecimal, and octal โ€” or enter any base and convert to the others. Includes step-by-step working.

โš  Invalid input for selected base

Binary / Decimal / Hex / Octal reference table

DecimalBinaryHexOctal

How to Convert Binary to Decimal

Each binary digit (bit) represents a power of 2, starting from 2โฐ = 1 on the right. To convert binary to decimal, multiply each bit by its corresponding power of 2 and sum the results. Example: 1101โ‚‚ = (1ร—2ยณ) + (1ร—2ยฒ) + (0ร—2ยน) + (1ร—2โฐ) = 8 + 4 + 0 + 1 = 13โ‚โ‚€.

How to Convert Decimal to Binary

Divide the decimal number repeatedly by 2 and record the remainder at each step. Read the remainders from bottom to top. Example: 13 รท 2 = 6 remainder 1 โ†’ 6 รท 2 = 3 remainder 0 โ†’ 3 รท 2 = 1 remainder 1 โ†’ 1 รท 2 = 0 remainder 1. Reading remainders bottom-up: 1101.

Binary, Decimal, Hexadecimal, and Octal

These are all number bases (positional notation systems). Binary (base-2) uses digits 0-1. Octal (base-8) uses 0-7. Decimal (base-10) uses 0-9. Hexadecimal (base-16) uses 0-9 and A-F (A=10, B=11, C=12, D=13, E=14, F=15). Computers internally use binary; hex is a compact human-readable representation of binary (each hex digit = 4 bits); octal is common in Unix file permissions.

Multiply each bit by 2 raised to its position (right=0), sum all results. 1101 = 8+4+0+1 = 13. The converter above shows the step-by-step working.
1010 binary = 10 decimal. (1ร—8) + (0ร—4) + (1ร—2) + (0ร—1) = 8+0+2+0 = 10.
A base-2 system using only 0 and 1. It is the foundation of all computer data because electronic circuits represent two states: on (1) and off (0).
Repeatedly divide by 2 and record remainders. Read them bottom-up. 13 โ†’ remainders: 1,0,1,1 โ†’ read up: 1101.