How unit conversion works
Each unit is first converted into the base unit of its family — the metre, kilogram, square metre, litre or second — and then divided by the target unit. The calculator prints that multiplier, so the whole sum is visible.
Unit conversion calculators
Length, mass, area, volume and time — five converters that show the multiplier outright, so you can see where the answer comes from.
Length converterMillimetres, centimetres, metres, kilometres, inches, feet, mileslength converterMass converterMilligrams, grams, kilograms, tonnes, ounces, poundsmass converterArea converterSquare millimetres, centimetres, metres, ares, hectares, square kilometresarea converterVolume converterMillilitres, litres, cubic centimetres, cubic metres, gallonsvolume converterTime converterSeconds, minutes, hours, days, weeks, months, yearstime converter
Watch out for squared and cubed units
A metre is 100 centimetres, but a square metre is already 10,000 square centimetres, and a cubic metre a million cubic centimetres. For area the multiplier is squared and for volume it is cubed — the most common mistake in these questions.
Frequently asked questions
10,000. The length multiplier (100) is squared, because area has two dimensions.
1.5 hours. The time converter handles seconds, minutes, hours, days, weeks, months and years.
Yes — inches, feet and miles for length, and ounces and pounds for mass, alongside the metric units.
Units tripping you up?
Book a free introductory lesson with a Mathema tutor. 30 minutes online, no commitment — we find the gap and the plan to close it.