Units & conversions
Length, area, volume, speed, data and temperature, 200+ units.
Numbers can carry units, and OtterCalc keeps them straight. Add compatible units and it converts for you; add incompatible ones, like kilometers plus kilograms, and you get a clear error instead of a wrong answer.
Converting
Convert with "to" or "in". Spanish speakers can also write "a": 5 kilometros a millas works.
Area, speed and data
Everyday notations are understood: m2 or m² for square meters, mph and kph for speed, gb and mb for file sizes.
Pressure, torque, data rates and electricity
Past the everyday units there is a long tail, all built in. Pressure reads psi, bar and pascal. Torque takes ftlb, or write N*m for the metric side. Data rates understand Mbps and Gbps. The electrical family covers watts, kilowatt-hours, volts, ohms and hertz. One quirk: amperes are amp or amps, because a bare A reads as the word "a".
Fuel economy and cooking
Two conversions that are not simple unit swaps still work. Fuel economy flips between mpg and L/100km (they are reciprocals; add imperial for the UK gallon). Cooking crosses weight and volume when you name the ingredient, so grams become cups using that ingredient's density.
Keep calculating after a conversion
A conversion does not have to end the line. Whatever follows applies to the converted result, so you can convert and then divide, multiply or add in one go.
Invent your own units
Declare a unit the same way you declare an exchange rate, then use it anywhere in the document. Plurals just work, and units can build on each other, so a crate can be worth four boxes and a box a dozen eggs. A unit defined in money even converts through your exchange rates.
One sharp corner
The words min and sec mean minutes and seconds after a number or after to (90 sec to min), and min is the minimum function before parentheses. Both lines below do what you expect.