Length Converter
Enter a value and select units to convert between metric and imperial length measurements.
Reviewed by Richard Ross · Last updated April 2026
How Length Converter works
Metric length units
The metric system uses powers of 10: 10 mm = 1 cm; 100 cm = 1 m; 1,000 m = 1 km. The metre is the SI base unit of length.
Imperial length units
12 inches = 1 foot; 3 feet = 1 yard; 1,760 yards = 1 mile. The UK uses both metric and imperial in everyday life: road distances in miles, heights in feet and inches, fabric in metres.
Key conversions
1 inch = 2.54 cm exactly. 1 foot = 30.48 cm. 1 mile = 1.60934 km. 1 metre = 3.28084 feet.
Real-world use cases
Length conversions come up constantly in UK daily life. Estate agents list room dimensions in both metres and feet. DIY projects often mix metric timber sizes with imperial drill bit diameters. Athletics tracks are 400 metres; road races use miles and kilometres side by side. Tailors work in centimetres while some clothing sizes still reference inches.
UK-specific context: the metric muddle
The UK began metrication in 1965 but never completed it. Road signs remain in miles and yards under law. Pubs serve drinks in pints. Yet supermarkets price goods per kilogram and builders order timber in millimetres. This dual system means many people need to convert lengths regularly — particularly the older generation comfortable in feet and inches and younger people educated in metric.
Precision and rounding
The inch–centimetre conversion (1 in = 2.54 cm) is exact by international agreement. All other conversions follow from this. When measuring for construction or manufacturing, carry at least 4 significant figures to avoid compounding rounding errors across multiple steps. For casual use — checking a room size or comparing a waist measurement — 2 decimal places is sufficient.
Frequently asked questions
How many cm in an inch?
Exactly 2.54 cm. So 1 inch = 2.54 centimetres.
How many feet in a metre?
1 metre = 3.28084 feet. Or conversely, 1 foot = 0.3048 metres.
How many miles in a kilometre?
1 km = 0.621371 miles. Or 1 mile = 1.60934 km.
What is the difference between a yard and a metre?
A metre is slightly longer than a yard. 1 metre = 1.09361 yards. 1 yard = 0.9144 metres.
How do I convert my height from feet and inches to centimetres?
Multiply the feet by 30.48, then add the inches multiplied by 2.54. For example, 5 ft 10 in = (5 × 30.48) + (10 × 2.54) = 152.4 + 25.4 = 177.8 cm.
Why does the UK still use miles on road signs?
UK road signs are legally required to display distances in miles under the Traffic Signs Regulations 2016. Switching to kilometres would require replacing hundreds of thousands of signs at significant cost. There is no current government plan to change this.
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