Number Converters

Binary, octal, decimal and hex conversions, Roman numerals, words and fractions.

Decimal to Binary ConverterConvert decimal numbers to binary (base 2), with optional 4- or 8-bit digit grouping. Handles huge and negative numbers.Binary to Decimal ConverterConvert binary numbers to decimal. Accepts 0b prefixes, spaces and underscores between digits, and any length.Decimal to Hex ConverterConvert decimal numbers to hexadecimal (base 16) in upper or lower case, with an optional 0x prefix.Hex to Decimal ConverterConvert hexadecimal numbers (with or without 0x) to decimal, with exact results for 64-bit values and beyond.Decimal to Octal ConverterConvert decimal numbers to octal (base 8), useful for Unix file permissions and legacy systems.Octal to Decimal ConverterConvert octal (base 8) numbers such as 755 or 0o644 to decimal values.Binary to Hex ConverterConvert binary numbers to hexadecimal; every four bits become one hex digit.Hex to Binary ConverterConvert hexadecimal numbers to binary, optionally grouped into nibbles or bytes for readability.Binary to Octal ConverterConvert binary numbers to octal; every three bits become one octal digit.Octal to Binary ConverterConvert octal numbers to binary, for example to read Unix permission bits like 755.Hex to Octal ConverterConvert hexadecimal numbers to octal (base 8) exactly, regardless of size.Octal to Hex ConverterConvert octal numbers to hexadecimal with optional 0x prefix and lower-case output.Number Base ConverterConvert whole numbers between any bases from 2 to 36, including binary, octal, decimal, hex and base 36.Number to Roman Numerals ConverterConvert numbers from 1 to 3999 to standard Roman numerals such as MMXXIV, one per line.Roman Numerals to Number ConverterConvert Roman numerals to numbers with validation of the standard subtractive form.Number to Words ConverterSpell out numbers in English words, up to the quintillions, including negatives and decimals.Words to Number ConverterConvert English number words like "two thousand and twenty-four" back into digits, including decimals.Scientific Notation ConverterConvert numbers to and from scientific, E or engineering notation exactly, with optional significant-figure rounding.Decimal to Fraction ConverterConvert decimals, including repeating decimals like 0.(3), to simplified fractions or mixed numbers.Fraction to Decimal ConverterConvert fractions and mixed numbers to decimals, rounded to a chosen precision or with repeating digits marked.Percentage CalculatorWork out X% of Y, what percent X is of Y, percentage change, increases, decreases and percentage difference.Two’s Complement ConverterConvert signed integers to and from two’s complement binary and hex at 8, 16, 32 or 64 bits.