Length Converter
Convert any length between metric and imperial units: millimeters, centimeters, meters, and kilometers on one side; inches, feet, yards, and miles on the other. Enter a value, pick the units, and the result updates as you type.
- 5 km in mi
- 3.106856 mi
Length conversions come up constantly: reading product dimensions from another country, following overseas driving distances, checking your height in feet for a form, or translating a DIY plan. The imperial–metric boundary is where most mistakes happen, so the key conversion factors are listed below.
How it's calculated
1 inch = 2.54 cm (exact) · 1 foot = 0.3048 m · 1 mile = 1.609344 km
All conversions go through meters as a base unit: the value is multiplied into meters, then divided by the target unit's factor. The inch was defined as exactly 25.4 mm by international agreement in 1959, which makes every derived factor exact.
Worked example
A 5K run is 5 × 0.621371 = 3.11 miles. A person 5 ft 9 in tall measures 5×30.48 + 9×2.54 = 175.26 cm. A 32-inch TV diagonal is 81.28 cm.
Frequently asked questions
›How many centimeters are in an inch?
Exactly 2.54 cm. This is a defined value, not an approximation. Going the other way, 1 cm ≈ 0.3937 inches.
›How do I convert my height between feet and centimeters?
Multiply feet by 30.48 and inches by 2.54, then add. For example, 6 ft 1 in = 6×30.48 + 2.54 = 185.4 cm. To go back, divide by 2.54 for total inches, then split by 12.
›How long is a mile compared to a kilometer?
A mile is 1.609 km, about 61% longer than a kilometer. A quick mental trick: multiply miles by 8/5 to estimate kilometers.
›Which countries still use imperial lengths?
The United States uses them for most everyday purposes; the UK mixes both (miles for roads, meters elsewhere). Nearly every other country uses metric exclusively.
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