What is binary to decimal conversion?

Binary (base-2) uses only digits 0 and 1, while decimal (base-10) uses digits 0-9. Converting binary to decimal involves multiplying each binary digit by 2 raised to the power of its position, then summing the results. For example, binary 1010 equals (1×8) + (0×4) + (1×2) + (0×1) = 10 in decimal.

// JavaScript — binary ↔ decimal
parseInt('1010', 2);          // 10 (binary to decimal)
(10).toString(2);             // '1010' (decimal to binary)
parseInt('11111111', 2);      // 255
(255).toString(2);            // '11111111'

# Python — binary ↔ decimal
int('1010', 2)    # 10 (binary to decimal)
bin(10)           # '0b1010' (decimal to binary)
format(10, 'b')   # '1010' (without 0b prefix)

Common use cases for binary-decimal conversion

Binary to decimal conversion is fundamental in computer science education, programming (especially for bit manipulation and bitwise operations), networking (IP address calculations), and understanding how computers represent numbers internally. It is also used in digital electronics and embedded systems programming.