Unit converter for every measurement

An online tool for converting units of measurement: type the value the way you would ask a search engine, like "5 ft 11 in to cm", "72 F" or "30 mpg to l/100km", and see the answer in every unit of that quantity at once. The measurement converter works from the exact definitions of the units and tells you whether the answer is exact or rounded.

How to use it

Type a value

A number and a unit, such as "180 cm". To get a specific unit, add "to ft".

Check the answer and how it was read

The big line is the most useful unit, with two more below it and a "Read as" line so you can check how the query was understood.

Check the other units

The table shows the value in every unit. Tap a number to copy it, or tap a unit name to convert from it.

Or pick a quantity

If you would rather not type, tap Length, Pressure or another quantity and choose a unit in the table.

Convert feet to centimeters, Fahrenheit to Celsius and miles to kilometers in one line

What to convert

Type a value, such as "5 ft 11 in to cm", or pick a quantity below.

For example:

Length

Precision

Auto shows the exact value while it fits in 12 digits, otherwise 6 significant digits. Tap a number to copy it.

Features

A search-style input line

Reads "1.5 kg in lbs", "5 3/8 in", "5'11"", "1 h 30 min", "how many cm in a foot" and "1.5e3 m", with a decimal point or a comma.

An = or ≈ sign

Factors are exact by definition: an inch is exactly 2.54 cm and a pound is 0.45359237 kg. The = sign means the answer was not rounded.

Every unit of the quantity at once

Below the answer is a table of all units aligned on the decimal point. Tap a number to copy it and pin the units you use most.

The details people get wrong

TB vs GiB, bits vs bytes, hp vs PS, the tire-gauge atmosphere, US vs imperial gallons, each explained right under the answer.

Inverse quantities

Fuel economy converts between mpg and l/100 km, and a running pace of 8:30 min/mi converts to mph, by division rather than a plain factor.

A link to the answer

The page address keeps your query, so a link shows someone the same conversion. Recent queries stay under the input line.

Frequently asked questions

Why does Windows show my 1 TB drive as 931 GB?

The manufacturer counts a terabyte as decimal, 10¹² bytes. Windows divides by 1,024 three times and shows gibibytes, but labels them "GB". 10¹² ÷ 1,024³ = 931.32, hence the "missing" 69 GB. Here the two are kept apart: kB, MB and GB are decimal, KiB, MiB and GiB are binary.

What do the = and ≈ signs before the answer mean?

Nearly every unit is defined exactly: an inch is exactly 25.4 mm, a pound is exactly 0.45359237 kg and an atmosphere is exactly 101,325 Pa. The converter calculates with fractions rather than floating-point numbers, so it knows whether the value was cut off for display. = means the answer is complete, ≈ means it was rounded to the chosen precision or the unit itself is approximate, like the radian or Mach.

How do I convert mpg to liters per 100 km?

They are inverses: the more miles per gallon, the fewer liters per 100 km. So the formula divides instead of multiplying: l/100 km = 235.215 ÷ mpg for US gallons and 282.481 ÷ mpg for imperial ones. Type "30 mpg to l/100km" to get 7.84.

Is horsepower the same everywhere?

No. US and UK horsepower (hp) is defined through feet and pounds, 550 foot-pounds per second, which is 745.7 W. The metric horsepower used on European car documents (PS, CV, ch) is 75 kgf·m per second, 735.5 W. So 200 hp is about 203 PS.

Why are there two kinds of gallon and pint?

The US kept the old wine gallon of 231 cubic inches (3.785 l), while Britain defined the imperial gallon in 1824 as 4.54609 l. Pints and fluid ounces follow their gallons, with one twist: an imperial pint has 20 fluid ounces and a US pint has 16. A plain "gallon" here is the US one, and the imperial reading is one tap away.

How do I enter feet and inches or hours and minutes?

The way you would write them: "5 ft 11 in", "5'11"" or "5 ft 11", where the converter fills in the inches. Time works as "1 h 30 min", "1:30" or "1:30:00", and running pace as "8:30 min/mi". Fractions of an inch work too: "5 3/8 in" or "⅜".

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Published 28 Oct 2026 Author: The Supreme