Length Converter
Convert meters, feet, inches, miles, and kilometers.
This length converter switches between metric units (millimeters, centimeters, meters, kilometers) and imperial/US units (inches, feet, yards, miles), each conversion using a fixed multiplication factor between the two.
Enter a length in any supported unit, and the calculator returns the equivalent in your chosen target unit.
Worked Calculation Examples
| Scenario | Result | Calculation Step |
|---|---|---|
| 10 miles to kilometers | 16.0934 km | 10 × 1.60934 = 16.0934 km. |
| 5 feet 6 inches to centimeters | 167.64 cm | 66 × 2.54 = 167.64 cm. |
Key Length Conversion Factors
1 inch = 2.54 centimeters exactly, which anchors most metric-imperial length conversions. From there, 1 foot = 12 inches = 30.48 cm, 1 yard = 3 feet = 0.9144 m, and 1 mile = 5,280 feet = 1.60934 km - each derived from the base inch-to-centimeter relationship.
Why the US Still Uses Imperial Units
While most of the world uses the metric system for everyday measurement, the US continues to primarily use imperial units in daily life and many industries, making length conversion a common need for international collaboration, travel, and trade between metric and imperial-using contexts.
How to Use the Length Converter
- Open the Length Converter and enter the values requested in the input fields.
- Check the units, percentages, dates, or time periods before reading the answer.
- Review the instant result and adjust any value to compare another scenario.
- Use the formula, example, and FAQs below to understand how the length converter works.
Frequently Asked Questions
How many centimeters are in an inch?
Exactly 2.54 centimeters equal 1 inch - this is the defined conversion factor that underlies most metric-imperial length conversions.
How do you convert miles to kilometers?
Multiply the number of miles by 1.60934 to get kilometers, since 1 mile equals approximately 1.60934 km.
Why are there so many different length units?
Different measurement systems developed independently across regions and historical periods - the metric system was designed for decimal simplicity, while imperial units evolved from older, more informal reference measurements.
How do I use this length converter?
Enter the known values, review the units or settings, and the calculator updates the result instantly. The formula and example on this page show how the answer is produced.
What does the Length Converter calculate?
Convert meters, feet, inches, miles, and kilometers. It is designed for fast browser-based calculations without sign-up, downloads, or manual spreadsheet setup.
What formula does this length use?
The formula is: target = source * conversion factor. The metric system was created during the French Revolution in the 1790s, designed deliberately around powers of ten to replace the confusing patchwork of local, inconsistent measurement units used across pre-revolutionary France - the meter itself was originally defined as one ten-millionth of the distance from the North Pole to the equator, before later being redefined using atomic and light-based standards for greater precision.
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Last updated: September 27, 2026.