Binary to Decimal Converter

In binary every place is worth twice the place to its right: 1, 2, 4, 8, 16 and so on, from the right. To get the decimal value, add up the places that have a 1: 1011 is 8 + 2 + 1 = 11, and 11111111, eight ones, is 255, the largest value of a byte. Type or paste binary numbers, one per line, and the decimal values appear as you type; spaces between groups of digits, as in 1111 0000, and the prefix 0b are fine. Under the result, the converter shows the calculation for the first number: every digit times 2 to the power of its place, and the sum.

Binary fractions work too: the places after the point are worth one half, one quarter, one eighth and so on, so 1010.101 is 10.625. The conversion is exact for numbers of any length, also for 64 bits and more, where calculators start to round. If a line has a digit other than 0 and 1, it is listed under the result, so you see what to fix. Use “From” and “To” for octal, hex or any base from 2 to 36, “Group digits” for results such as 65 535, and “Swap” to convert the decimal numbers back to binary.