Convert numbers between binary, octal, decimal, and hexadecimal
Convert numbers between binary, octal, decimal, and hexadecimal, plus any custom base from 2 to 36. Each result also shows how the same bits would be read as a signed 8-bit, 16-bit, or 32-bit integer, and binary output is grouped into nibbles for readability. Beyond conversion, the tool has three more modes: a bitwise calculator, an IEEE-754 floating-point inspector, and an interactive ASCII table, which makes it a small workbench for low-level programming, memory addresses, and digital logic.
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You are debugging a bitmask and need to see the value 255 as hex, binary, and octal at once.
Decimal
255
Other bases
Hex: 0xFF Binary: 0b11111111 Octal: 0o377
255 is 2⁸−1, so it is all ones across 8 bits (`11111111`) and the single-byte maximum, instantly recognisable once you see the binary. The converter handles arbitrary bases 2–36 and large values without floating-point rounding, which matters when a 64-bit flag silently loses precision in less careful tools.
Convert numbers between binary, octal, decimal, and hexadecimal, plus any custom base from 2 to 36. Each result also shows how the same bits would be read as a signed 8-bit, 16-bit, or 32-bit integer, and binary output is grouped into nibbles for readability. Beyond conversion, the tool has three more modes: a bitwise calculator, an IEEE-754 floating-point inspector, and an interactive ASCII table, which makes it a small workbench for low-level programming, memory addresses, and digital logic.
The Base Converter mode parses your input in the base you select (it strips 0x, 0b, and 0o prefixes and ignores spaces and underscores) and re-displays it in decimal, binary, octal, hex, and a custom base you choose from 2 to 36. Because parsing goes through JavaScript numbers, it covers integers up to 2^53 - 1 exactly; it also shows the signed 8-, 16-, and 32-bit interpretations of the value so you can see how the same byte pattern reads as a negative number under two's complement.
The Bitwise mode takes one or two operands (each in its own base) and computes NOT, left shift, arithmetic right shift, zero-fill right shift, AND, OR, XOR, NAND, and NOR, showing each result in decimal, binary, and hex with the operands laid out in 8-bit groups. The IEEE-754 mode decodes a decimal number into its single-precision (32-bit) or double-precision (64-bit) floating-point representation, splitting out the sign bit, the biased and unbiased exponent, and the mantissa, and reconstructing the value as a formula; quick buttons load pi, e, infinity, NaN, and the format's min and max. The ASCII mode renders an interactive table of code points 0-127, color-coded by control, digit, uppercase, and lowercase, with click-to-copy. Everything runs locally in your browser.
Yes. The Base Converter has a custom-base option that supports any base from 2 to 36, using digits 0-9 and letters A-Z.
The base converter works on unsigned magnitudes, but it also shows the signed 8-, 16-, and 32-bit two's-complement interpretation of each value so you can read negative results directly.
The converter handles numbers up to JavaScript's safe integer limit (2^53 - 1). For larger values, results may lose precision.
Conversions run on your device in JavaScript. The values you enter are never sent over the network.