Unit conversion guide
Metric to Imperial Conversion Guide
Metric to imperial conversion explained for centimetres, metres, kilometres, kilograms, pounds, litres, gallons, square metres and more.
Updated 16 October 2026 • Reviewed by Tools by Layna Editorial Team • General information only
Metric to imperial conversion is one of the most common reasons people use a converter. Australia uses metric units, but imported products, US recipes, international fitness content and overseas property information often use imperial or US customary units.
Start with the unit family
Do not just search for a number. Work out whether the measurement is length, weight, volume, area, speed or temperature. The correct formula depends on the family. Feet, pounds and gallons are not interchangeable.
High-use conversions
The most common conversions are centimetres to inches, metres to feet, kilometres to miles, kilograms to pounds, litres to gallons and square metres to square feet. These cover product sizing, body measurements, recipes, fuel, travel and property comparisons.
Area needs special care
Area is where many people make a bad shortcut. One metre is 3.28084 feet, but one square metre is not 3.28084 square feet. It is about 10.7639 square feet because both length and width are converted.
Volume is not always weight
A litre is a volume unit and a kilogram is a mass unit. Water is close enough that people sometimes use them loosely, but oil, flour, protein powder and sugar do not follow the same relationship. Use a recipe or ingredient weight when accuracy matters.
Temperature uses an offset
Celsius to Fahrenheit is not a straight multiplication. You multiply by 9/5 and then add 32. Fahrenheit to Celsius subtracts 32 first. This is why temperature conversion needs its own converter.
Practical rule
Use metric for Australian decisions unless the source information is imperial. Convert for comparison, but keep the original unit noted so you do not lose context.
Use the correct family and preserve units
Metric and imperial conversion is not one universal operation. Length, area, volume, mass, temperature and speed each use different factors, and temperature additionally uses an offset. Identify the quantity first, then choose the factor for that quantity.
Area and volume require squared or cubed relationships. One metre is about 3.28084 feet, but one square metre is about 10.7639 square feet and one cubic metre is about 35.3147 cubic feet. Applying the length factor directly to area or volume creates a large error.
United States customary units and British imperial units are also not identical. The US liquid gallon is about 3.7854 litres while the imperial gallon is 4.54609 litres. Cups, pints and fluid ounces can also differ. Label the system rather than writing only “gallon” or “cup”.
For spreadsheets, store a source value, source unit, factor, unrounded result and display unit in separate fields. That makes the conversion auditable and prevents a later user from treating a rounded display value as the original measurement.
Sources and review notes
- National Measurement Institute — Australia’s National Measurement Institute maintains Australia’s measurement system and primary measurement standards. Use official measurement standards where legal, trade or technical precision matters.