Two’s Complement Calculator

This two’s complement calculator converts a signed whole number into the exact binary pattern a computer would store it in, using the scheme almost every processor relies on for negative integers. Enter any whole number, positive or negative, then choose a bit width of 8, 16 or 32 bits to match the size you are working with. The calculator returns three results: the two’s complement binary pattern padded to the full width, the equivalent hexadecimal value, and the unsigned decimal value that the same bit pattern represents if read without a sign. Two’s complement works by storing negative numbers as two to the power of the bit width plus the value, which makes the leftmost bit act as a sign bit, 1 for negative and 0 for zero or positive, and lets processors add and subtract without special-case logic for negative numbers. If your number falls outside the range the chosen width can hold, for example beyond minus 128 to 127 at 8 bits, the calculator flags it as out of range rather than showing a wrong answer, so you know to pick a wider width. It suits students learning binary arithmetic, programmers debugging low-level code, and anyone checking how a negative value looks in memory. Try the built-in example of minus 5 at 8 bits to see the working before entering your own numbers.

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