Unit Converters

This section or the conversion answers

Use a converter here when you have a number of your own to put in. If instead you have one standing question, such as how many cups are in a quart, the conversion answer pages give the number directly with the reasoning underneath, and there is nothing to type. The two sections cover overlapping units on purpose and are shaped for different moments.

Length Converter

for metric and imperial length in one place.

Temperature Converter

for Celsius, Fahrenheit and Kelvin, offsets handled properly.

Torque Converter

for newton metres and pound feet, with exact and derived factors kept apart.

Data Storage Converter

for bytes upward, with the decimal and binary conventions distinguished.

Where these calculations go wrong

Temperature does not scale like the rest

Most conversions are a single multiplication, so doubling the input doubles the output. Temperature is not: Celsius and Fahrenheit have different zero points, so the conversion has an offset as well as a factor and cannot be done by ratio.

Fuel economy runs backwards

Miles per gallon and litres per 100 km measure the same thing in opposite directions, so a higher number is better on one scale and worse on the other. Converting between them is an inverse relationship rather than a straight multiply, which is a common source of nonsense results.

Related sections

• Conversions for the fixed-question versions of the same units, answered directly.
• Home for the project tools these conversions usually feed into.