Convert binary numbers to decimal, or decimal to binary. It handles very long numbers, and explains how the conversion works.
Binary to decimal
Decimal to binary
Decimal
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Binary
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How it works
Each binary digit is worth a power of two, from right to left: 1, 2, 4, 8, 16 and so on. To convert binary to decimal, add the values of the positions that hold a 1. To convert decimal to binary, divide the number by 2 repeatedly and read the remainders backwards.
Example
1101 in binary is 8 + 4 + 0 + 1 = 13. And 13 divided by 2 gives remainders 1, 0, 1, 1, read backwards as 1101.
Frequently asked questions
How do I convert binary to decimal?
Add the powers of two for every digit that is 1.
What is 1010 in decimal?
10, because 8 + 2 = 10.
Can it convert large numbers?
Yes. It uses big integers, so length is not limited in practice.
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