Numbers, Bitwise & Units
Choose whether your input is a mathematical value or a stored bit pattern.
One integer, up to 256 characters. Optional 0b/0o/0x must match the base. No internal spaces, separators, line breaks or fractions.
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Value encodes a mathematical integer. Bit pattern reads a nonnegative word, padded with zeros on the left; it rejects a minus sign.
Changing an option reinterprets the existing text. Both byte orders use the final word and preserve the bit order inside each byte.
Input fits the selected range.
A two's complement calculator is useful when a register dump says FF but your debugger displays −1. Before changing either value, establish the word width and whether you are encoding a number or reading existing bits.
A signed binary converter needs more than a base selector. Here, the input meaning is explicit: a mathematical 255 cannot fit a signed byte, while the raw pattern FF fits perfectly and decodes to −1. Both readings remain visible beside the same stored word.
The two's complement calculator keeps 300 in your input while showing that only 44 remains in an 8-bit word. The warning separates integer overflow from invalid syntax. You can inspect the resulting bits and both decimal readings without accepting a replacement or losing the original number.
For 0x12345678 at 32 bits, the big-endian bytes are 12 34 56 78 and the little-endian bytes are 78 56 34 12. These are two layouts of one word. The value, sign and the internal order of each byte stay the same.
Start in Value mode to encode −42. For an existing FF dump, select Bit pattern and hexadecimal. A base change reinterprets the text; it never rewrites it. The default is decimal, signed, 8 bits, with automatic calculation enabled.
The width sets the sign position and the range. FF at 16 bits is 00FF, which reads as 255; it is not sign extension of an 8-bit −1. To keep the mathematical value −1 while widening, enter −1 in Value mode.
Automatic calculation waits 350 ms. Switch it off to use Calculate or Ctrl/Cmd + Enter. Every edit disables exports until recalculation. Example and Clear first show changed-field counts; applying can be undone together with the previous result.
For a word of width w, unsigned values run from 0 to 2^w−1 and signed values from −2^(w−1) to 2^(w−1)−1. The selected interpretation controls the main decimal reading, while both ranges remain available for comparison.
For −42 at 8 bits, the absolute value is 00101010. Invert all eight bits to get 11010101, then add one to obtain 11010110. This walkthrough appears for negative mathematical inputs inside the signed range, including its minimum value.
Integer parsing, range checks and formatting use exact integer arithmetic. The unsigned maximum 18446744073709551615 therefore remains intact. Binary and hex include leading zeros for the selected width; the report also records the original text and the parameters used to interpret it.
Choose Value mode, decimal, 8 bits and signed interpretation. Enter −5: the output is 11111011, or FB in hexadecimal. Its unsigned reading is 251, which describes the same eight bits rather than a second encoding.
The minimum is −2^(w−1) and the maximum is 2^(w−1)−1. For 8 bits this is −128 through 127; for 16 bits it is −32768 through 32767. The panel computes the exact limits for all four supported widths.
Select Bit pattern, choose the source base and width, then read Signed decimal. If the highest selected bit is set, subtract 2^w from the unsigned magnitude. For 8-bit 11111011, that is 251−256=−5.
A signed byte stops at 127. In Value mode, 200 receives a range warning and its retained pattern reads as −56. If 200 describes existing raw bits, use Bit pattern mode: the word fits and −56 is simply its signed interpretation.
Yes, within the supported input syntax and length. The calculation never converts the integer through a floating-point Number. For example, 9223372036854775808 is preserved and reads as −9223372036854775808 when its 64 bits are interpreted as signed.
Something looks wrong?
Use the two's complement calculator to inspect one boundary value, then change the input meaning or width and compare the result. Copy a fresh report with its original input, range status and both byte layouts.