Converters
Converters
Conversions between units of measurement, instant and with no tables to look up by hand.
How these conversions work
Every category goes through a single reference unit — the metre for lengths, the kilogram for masses, the joule for energy — so any conversion is the product of just two factors and the result picks up no intermediate rounding. Temperature is the exception: its scales differ by an origin as well as a slope, so zero degrees Celsius is not zero Fahrenheit and the conversion is not a plain multiplication. Below the result you will find the full table for the category, useful when you need to compare several units at once.
Unit converter
Length, mass, area, volume, temperature, speed, time, digital data, energy and pressure.
Days between dates and age
Days, weeks and months between two dates, weekdays, exact age and the date after a number of days.
Roman numerals
Convert numbers to Roman numerals and back, with the symbol-by-symbol breakdown.