Length conversions
Wrong unit labels break more spreadsheets than the formula: millimeters entered as centimeters, or trip kilometers pasted into a mile column. Each conversion goes to meters first, then to the unit you chose, so feet, miles, millimeters, etc. all share one meter definition.
How the converter works
Each unit has a fixed meter equivalent. Put the input in meters first, then divide by the target unit's meter factor.
Result = Value × (source unit in meters) ÷ (target unit in meters)
Example: The calculator opens with 1 m and km selected, so the readout shows 0.001 km until you pick another target. The same 1 m is 3.28084 ft or about 39.37 in if you switch units. 5 statute mi ≈ 8.05 km (5 × 1,609.34 ÷ 1,000).
Units in the dropdown
Factors below match the calculator’s internal meter equivalents.
Meter (m)
Factor: 1 (base unit)
SI base unit of length (defined via the speed of light since 2019). Global default for science, construction, and sport.
Kilometer (km)
Factor: 1 km = 1,000 m
Road signs and Strava in most countries. A marathon is 42.195 km (about 26.2 mi). 1 km = 1,000 m exactly.
Centimeter (cm)
Factor: 1 cm = 0.01 m
Body height and apparel in metric markets. 2.54 cm = 1 in exactly (1959 agreement).
Millimeter (mm)
Factor: 1 mm = 0.001 m
Machining, 3D prints, and rainfall totals. 25.4 mm = 1 in. Import sheets often mix mm and cm columns.
Mile (mi)
Factor: 1 mi = 1,609.34 m
US/UK road distance unit here: 1 mi = 1,609.34 m in this tool, with 5,280 ft and 1,760 yd per mile.
Yard (yd)
Factor: 1 yd = 0.9144 m
Football field markings, fabric, and golf. 1 yd = 0.9144 m exactly; 3 ft per yard.
Foot (ft)
Factor: 1 ft = 0.3048 m
US height, ceiling heights, and aviation in feet. 1 ft = 0.3048 m exactly (30.48 cm). Square feet are area, not this linear unit.
Inch (in)
Factor: 1 in = 0.0254 m
Screens (diagonal), fasteners, and US specs. 1 in = 25.4 mm exactly. Twelve inches make one foot.
Common length conversions at a glance
Frequent pairs using the same factors as the calculator. For more context on one pair, use the focused links at the bottom.
| From | To | Formula | Example |
|---|---|---|---|
| Meters | Feet | m × 3.28084 | 10 m = 32.81 ft |
| Feet | Meters | ft × 0.3048 | 6 ft = 1.83 m |
| Miles | Kilometers | mi × 1.60934 | 26.2 mi = 42.16 km |
| Kilometers | Miles | km × 0.621371 | 100 km = 62.14 mi |
| Inches | Centimeters | in × 2.54 | 12 in = 30.48 cm |
| Yards | Meters | yd × 0.9144 | 100 yd = 91.44 m |
Why metric and imperial coexist
Metric length uses decimal prefixes on the meter (move the decimal for cm, mm, km). US customary units grew from trade measures with ratios like 12 in per ft and 5,280 ft per mile.
A 1959 agreement pinned the inch to 25.4 mm and the foot to 0.3048 m. The yard is 0.9144 m. Imperial conversions built on those links are exact even when daily habits stay customary.
Road distance is usually km outside the US. Drawings may be in mm while the tape on site still shows feet and inches.
Length Conversion FAQ
Feet per meter
About 3.28084 ft per m (2 m ≈ 6.56 ft). Comes from 0.3048 m per ft by definition.
Miles per kilometer
About 0.621371 mi per km (10 km ≈ 6.21 mi). Statute mile here: 1,609.34 m.
Inches to centimeters
Multiply by 2.54 (exact definition). Twelve inches = 30.48 cm.
Feet and inches vs decimal feet?
“5 ft 10 in” is 70 in total (5×12+10), not 5.10 ft. Parse to one length before converting.
Metric vs US customary length
Metric lengths scale by tens from the meter. US customary uses 12 in per ft, 3 ft per yd, and 5,280 ft per mile. Road signs are mostly km outside the US.