All-Unit Results
Based on the value you enter, here's how it converts across every supported length unit at once.
| Unit | Value |
|---|
Supported Units
This converter supports the metric, imperial/US customary, nautical, and scientific length units listed below, so you can convert between virtually any two length measurements you're likely to come across.
Metric Units
Nanometer, micrometer, millimeter, centimeter, decimeter, meter, kilometer.
Imperial & US Units
Inch, foot, yard, mile.
Nautical & Scientific
Nautical mile, light-year, astronomical unit, parsec.
How Length Conversion Works
Choose Your Units
Select the "From" unit and the "To" unit using the two dropdowns.
Type a Value
Enter a number in either box — whichever one you prefer.
See the Result
The other box updates instantly, with no button to click.
Common Length Conversion Formulas
Exact Conversion Factors
This converter uses internationally defined, exact conversion factors rather than rounded approximations:
| Relationship | Exact Value |
|---|---|
| 1 inch | = 2.54 cm |
| 1 foot | = 0.3048 m |
| 1 yard | = 0.9144 m |
| 1 mile | = 1,609.344 m |
| 1 nautical mile | = 1,852 m |
| 1 meter | = 3.28084 ft (approx.) |
| 1 kilometer | = 0.621371 mi (approx.) |
Conversion Chart
A quick reference chart for the unit pair currently selected above (cm to in). Change the units in the converter to update this chart.
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Frequently Asked Questions
What is a length converter?
A length converter is a tool that changes a measurement from one unit of length into another, such as centimeters into inches or miles into kilometers, by multiplying or dividing by a fixed conversion factor.
This tool converts between metric units (millimeters through kilometers), imperial and US customary units (inches, feet, yards, miles), nautical miles, and a few scientific distance units, all from a single two-way converter.
How do I convert cm to inches?
Divide the number of centimeters by 2.54 to get inches, since 1 inch is defined as exactly 2.54 centimeters.
Using this converter, select Centimeters on one side and Inches on the other, then type your value into either box — the result appears instantly without clicking anything.
How many inches are in 1 centimeter?
There are approximately 0.3937 inches in 1 centimeter.
This comes directly from the internationally defined relationship that 1 inch equals exactly 2.54 centimeters, so 1 centimeter equals 1 divided by 2.54 inches.
How many feet are in a meter?
There are approximately 3.28084 feet in 1 meter.
This is based on the exact definition that 1 foot equals 0.3048 meters, so 1 meter equals 1 divided by 0.3048 feet.
How many centimeters are in a foot?
There are exactly 30.48 centimeters in 1 foot.
This is exact rather than approximate, since 1 foot is internationally defined as 0.3048 meters, and 0.3048 meters equals 30.48 centimeters.
How do I convert miles to kilometers?
Multiply the number of miles by 1.609344 to get kilometers, since 1 mile is defined as exactly 1,609.344 meters.
Select Miles and Kilometers in the converter above and type into either field to get an instant, exact result.
What is the difference between metric and imperial units?
Metric units (millimeters, centimeters, meters, kilometers) scale by powers of 10, making conversions between them a matter of moving a decimal point.
Imperial and US customary units (inches, feet, yards, miles) use less uniform ratios rooted in historical measurement systems, such as 12 inches per foot and 5,280 feet per mile, which is why converting between the two systems needs a fixed conversion factor rather than a simple decimal shift.
Is this length converter accurate?
Yes. This converter uses internationally standardized, exact conversion factors (for example, 1 inch = 2.54 cm and 1 mile = 1,609.344 m) rather than rounded approximations.
Only the final displayed result is rounded, not the underlying calculation, so results are accurate to whatever decimal precision you choose in the precision dropdown.
Can I convert feet and inches to centimeters?
Yes. Convert each part separately and add the results together — for example, for 5 feet 8 inches, convert 5 feet to centimeters and 8 inches to centimeters using the tool above, then add the two results.
A combined feet-and-inches height converter is a natural addition for exactly this use case, and is worth using directly if you frequently convert heights.
What length units are supported?
Nanometers, micrometers, millimeters, centimeters, decimeters, meters, and kilometers on the metric side; inches, feet, yards, and miles on the imperial/US side.
Also included: nautical miles, plus light-years, astronomical units, and parsecs for scientific/astronomical distances.