CloudCalcAppLength Converter
Convert between millimeters, centimeters, meters, kilometers, inches, feet, yards, and miles - enter a value and choose your From and To units.
Last updated September 15, 2026
Enter a value to see the conversion.
Quick Length Conversion Reference
| Relationship |
|---|
| 10 mm = 1 cm |
| 100 cm = 1 m |
| 1,000 m = 1 km |
| 12 in = 1 ft |
| 3 ft = 1 yd |
| 1 in = 2.54 cm |
| 1 m ≈ 3.2808 ft |
| 1 km ≈ 0.6214 mi |
Examples
1 meter to centimeters
- Value:
- 1
- From Unit:
- Meters (m)
- To Unit:
- Centimeters (cm)
1 meter equals 100 centimeters.
10 kilometers to miles
- Value:
- 10
- From Unit:
- Kilometers (km)
- To Unit:
- Miles (mi)
10 kilometers equals approximately 6.2137 miles.
12 inches to feet
- Value:
- 12
- From Unit:
- Inches (in)
- To Unit:
- Feet (ft)
12 inches equals 1 foot.
170 centimeters to feet
- Value:
- 170
- From Unit:
- Centimeters (cm)
- To Unit:
- Feet (ft)
170 centimeters equals approximately 5.5774 feet.
Common Uses of Length Conversion
- Height - comparing a height given in centimeters or meters against feet and inches. See centimeters to feet or meters to feet.
- Running & distance - converting race and travel distances between kilometers and miles. See kilometers to miles.
- Engineering & precision - converting fine measurements and tolerances between millimeters and inches. See millimeters to inches.
- Everyday & product dimensions - checking clothing, furniture, or product measurements given in centimeters against inches. See centimeters to inches.
- Exact imperial conversion - converting a feet-and-inches measurement, such as from a tape measure, into a single unit. See feet to inches.
Metric Length Units
Metric length units scale by powers of ten, so converting between them is always a matter of shifting a decimal point.
- Millimeter (mm) -
- One thousandth of a meter - the smallest metric length unit in common everyday use.
- Centimeter (cm) -
- One hundredth of a meter - a convenient metric unit for everyday, hand-held-scale objects.
- Meter (m) -
- The SI base unit of length, defined by the distance light travels in a fixed, exact fraction of a second.
- Kilometer (km) -
- One thousand meters - the standard metric unit for longer distances.
Imperial and US Length Units
Imperial and US customary length units use traditional, non-decimal ratios rather than powers of ten.
- Inch (in) -
- A US customary and imperial unit equal to exactly 2.54 centimeters.
- Foot (ft) -
- A US customary and imperial unit equal to exactly 12 inches.
- Yard (yd) -
- A US customary and imperial unit equal to exactly 3 feet.
- Mile (mi) -
- A US customary and imperial unit equal to exactly 5,280 feet - the standard unit for long distances in the US and UK. That is also exactly 1,760 yards.
FAQ
How does this length converter work?
It converts your value through meters as a single canonical base unit: your value is first converted to meters using the From unit's exact conversion factor, then that meters value is converted into the To unit using its own exact factor. This two-step approach avoids the accumulated rounding error a direct unit-to-unit table can introduce as more units are added.
What is the difference between metric and imperial length units?
Metric units (millimeters, centimeters, meters, kilometers) scale by powers of ten and are the standard in science and most countries. Imperial units (inches, feet, yards, miles) use traditional, non-decimal ratios (12 inches per foot, 3 feet per yard, 5,280 feet per mile) and remain in everyday use in the United States. This calculator converts freely between both systems.
Why does this calculator use meters as the base unit?
The meter is the SI (International System of Units) base unit of length, and every unit this calculator supports - metric or imperial - has an exact, internationally defined conversion factor to meters. Routing every conversion through one common base unit keeps the calculation simple and exact, rather than needing a separate formula for every possible pair of units.
Does this calculator support decimal values?
Yes. Enter any decimal value (e.g. 2.5) and it converts normally. Results are shown to 4 decimal places by default; a very small result that would otherwise round to 0 is shown with additional decimal places instead, so a genuinely nonzero result is never displayed misleadingly as zero.
Does this calculator accept negative values?
No. A length cannot be negative, so the calculator rejects a negative value rather than returning a meaningless negative result. Zero is accepted, since a length of zero is valid.
This converter works by converting your value to meters first, then from meters into your chosen unit - so every conversion uses the same exact factors regardless of which two units you pick. Results are rounded to 4 decimal places, and converting a value to its own unit always returns that value unchanged.
Related Calculators
Weight Converter
Weight & MassConvert between milligrams, grams, kilograms, metric tons, ounces, pounds, stone, and US tons - enter a value and choose your From and To units.
Volume Converter
VolumeConvert between milliliters, liters, cubic meters, and US fluid ounces, cups, pints, quarts, and gallons - enter a value and choose your From and To units.
Temperature Converter
TemperatureConvert between Celsius, Fahrenheit, and Kelvin - enter a temperature and choose your From and To scales. Negative temperatures are accepted; values below absolute zero are not.