Convert length between metric and imperial: mm, cm, m, km, inches, feet, yards, and miles. All units at once.
Enter a length in any unit and instantly see the equivalent in all metric and imperial units: millimetres, centimetres, metres, kilometres, inches, feet, yards, and miles. All conversions use exact defined ratios — results are shown to 6 significant figures.
Type a value in the number box and select the source unit from the dropdown. All other units update instantly in the cards below.
Most mistakes around length are not maths mistakes. They happen because one number is in the wrong unit. A product page says 47 inches, your room plan is in centimetres, your courier asks for dimensions in millimetres, and your brain tries to bridge the gap with a rough guess. That is usually where the trouble starts.
This tool converts one length into millimetres, centimetres, metres, kilometres, inches, feet, yards, and miles at the same time. Instead of converting pair by pair, you enter the number once, keep the source unit visible, and read the unit you need.
Length conversion shows up in a few predictable places:
If the task involves buying, cutting, fitting, packing, or comparing, converting first is usually cheaper than correcting later.
People often treat feet and inches as if they were decimal feet. They are not. A measurement like 5 ft 8 in is not 5.8 feet. It is 68 inches, or about 172.7 cm. If you enter a mixed imperial measurement, convert it to a single unit first.
A wardrobe listed as 180 cm high may sound fine until the width is given in inches somewhere else on the page. Converting everything to one system before you compare it with your space is the safest approach.
Carrier limits are often tight enough that rounding early can create avoidable fees. A box that is 60.4 cm long may matter if the limit is 24 inches. Use the exact result first, then decide how much rounding the booking form allows.
A desk listed at 47 inches wide is about 119.4 cm. If your alcove is 120 cm wide, the desk technically fits, but only just. That is exactly the kind of situation where a rough “47 inches is about 120” estimate is not good enough.
A 10K is 6.21 miles. If you are used to 5-mile training runs, converting the event distance gives you a realistic idea of the gap instead of relying on instinct.
If a drawing shows one part as 25.4 mm and another note says 1 inch, those match exactly. Running suspicious measurements through one converter is a quick way to spot whether a mixed-unit drawing is internally consistent.
This tool converts linear distance only. It does not calculate area, volume, material quantities, or cutting plans. If your next question is about square metres, cubic feet, or coverage, that is a different calculation.
All conversions use exact or internationally-defined ratios (e.g. 1 inch = 25.4 mm exactly). Results are shown to 6 significant figures.
A statute mile is 1,609.34 m. A nautical mile is 1,852 m — about 15% longer — and is used in aviation and maritime navigation.
This tool runs entirely in your browser. Nothing you type or paste is sent to any server — all processing happens locally on your device.