Metric vs Imperial Units Explained with Conversion Tables
The metric system uses metres, grams and litres and scales by powers of 10. The imperial (and US customary) system uses inches, feet, pounds and gallons with mixed factors. Key conversions: 1 inch = 2.54 cm, 1 mile = 1.609 km, 1 kg = 2.205 lb, 1 US gallon = 3.785 L.
Who uses which system
✓📏 Nearly every country uses metric for science, trade and daily life. The United States mainly uses US customary units (similar to imperial), and the UK uses metric for most things but keeps miles on road signs and pints for milk and beer. That is why recipes, product labels and travel information often show both.
Length
| Imperial | Metric |
|---|---|
| 1 inch | 2.54 cm |
| 1 foot (12 in) | 30.48 cm |
| 1 yard (3 ft) | 0.9144 m |
| 1 mile | 1.609 km |
Weight
✓| Imperial | Metric |
|---|---|
| 1 ounce | 28.35 g |
| 1 pound (16 oz) | 453.6 g |
| 1 stone (14 lb) | 6.35 kg |
| 1 US short ton | 907.2 kg |
Volume
| Unit | US | UK (imperial) |
|---|---|---|
| Fluid ounce | 29.57 ml | 28.41 ml |
| Pint | 473 ml | 568 ml |
| Gallon | 3.785 L | 4.546 L |
Temperature
Metric countries use Celsius; the US uses Fahrenheit. °F = °C × 1.8 + 32. See the Temperature Converter.
Handy estimates
- 1 metre is a little more than 1 yard (about 3.3 ft).
- 1 kg is just over 2 pounds.
- 1 litre is a little more than 1 US quart.
- 5 miles ≈ 8 km; 100 km/h ≈ 62 mph.
Convert exactly
- Length Converter – 30+ units from nanometres to light years.
- Weight Converter – kg, lb, ounces, stones, tons, carats.
- Volume Converter – litres, gallons, pints, cups.
- Area Converter – square feet, acres, hectares.
Open the Length Converter on pdfseotools.com – free, no sign-up and it works on any device.
Häufig gestellte Fragen
Which countries use the imperial system?
The United States uses US customary units for most everyday measurements. The UK uses a mix – miles and pints alongside metric for most other things. Almost every other country uses metric.
Why is metric easier?
Units scale by 10: 10 mm = 1 cm, 100 cm = 1 m, 1,000 m = 1 km. Imperial units use mixed factors such as 12 inches in a foot and 5,280 feet in a mile.
Are US and UK gallons the same?
No. A US gallon is 3.785 litres; a UK (imperial) gallon is 4.546 litres.
How many cm are in an inch?
Exactly 2.54 cm.
How do I convert miles to kilometres?
Multiply by 1.609. A quick estimate: 5 miles ≈ 8 km.
Is a metric ton the same as a ton?
A metric tonne is 1,000 kg. A US (short) ton is about 907 kg and a UK (long) ton about 1,016 kg.
Zusammenfassung
Metric scales by ten; imperial uses mixed factors. Remember 2.54 cm per inch, 1.609 km per mile and 2.205 lb per kg, and use the free unit converters for anything exact.
Teilen in sozialen Medien: