Binary to Decimal Converter

How it is calculated

The input is stripped of all spaces, so 1111 0000 is read as 11110000. It must then consist only of the digits 0 and 1. The value is computed as decimal = Σ dᵢ × 2i, where dᵢ is the digit at position i counted from the right starting at 0. The hexadecimal output is the same number written in base 16 with an 0x prefix and upper-case letters. Leading zeros are ignored, and an input of only zeros gives 0 (0x0). The converter handles unsigned values of up to 63 binary digits after leading zeros are removed, i.e. up to 9223372036854775807; a longer string, or one containing any other character (a minus sign, a decimal point, the digit 2), returns no result. It does not interpret the leading bit as a sign.

Common mistakes

• Pasting a binary number with a prefix such as 0b or a trailing b. Only 0 and 1 are accepted, so the letter makes the input invalid; remove the prefix first.
• Expecting two's-complement negative numbers. A string like 11111111 is read as 255, not -1, because the tool never treats the leading bit as a sign.
• Entering fractional binary such as 101.1. A point is rejected; the tool only converts whole numbers.
• Counting positions from the left instead of the right. The rightmost digit is worth 1, so reversing the string gives a completely different value.
• Pasting a 64-bit all-ones value. Anything longer than 63 digits after leading zeros is refused rather than rounded.