Notation conversions

Roman numerals, data storage prefixes, fuel economy measures and angle units: conversions where the notation itself is the hard part.

• Roman Numeral Converter

  Convert numbers to Roman numerals and back, from 1 to 3999, with each numeral checked against the rules and a rejected one told which rule it breaks.

• Data Storage Converter

  Convert between bits, bytes, decimal GB and TB and binary GiB and TiB, see why a 1 TB drive shows as 931 GB, and how long a file takes at a given speed.

• Fuel Economy Converter

  Convert fuel economy between US mpg, imperial mpg, km per litre and litres per 100 km, with the cost per mile and km when you add a fuel price.

• Degrees and Radians Converter

  Convert angles between degrees, radians, gradians and turns, with radians given exactly as a multiple of π, such as π/6 for 30°, as well as in decimals.

• Military Time Converter

  Convert a 12-hour AM or PM time to military and 24-hour time, or a military time such as 1430 back to the 12-hour clock.

• Unix Timestamp Converter

  Convert a Unix timestamp in seconds or milliseconds to a UTC date and time, or a UTC date and time back to a Unix timestamp.

• Fraction to Decimal Calculator

  Write a fraction or mixed number as an exact decimal, with the repeating digits marked, and rounded to the number of places you choose.

• Color Converter

  Convert a colour between hex, RGB and HSL notation, using the conversions in the CSS Color Module Level 4 specification.

• DMS Converter

  Convert latitude, longitude or any angle between degrees, minutes and seconds and decimal degrees, with degrees and decimal minutes as well.

• Lakh and Crore Converter

  Write any number the Indian way, in lakh and crore with Indian commas and in words, next to the international million and billion form, with cheque wording.