To convert feet to meters, multiply by 0.3048. Meters to feet: multiply by 3.281. Miles to kilometers: multiply by 1.609. Kilometers to miles: multiply by 0.621. A person 5 feet 10 inches tall is 70 × 0.0254 = 1.778 meters. The US uses the imperial system while most of the world uses metric, making these conversions a constant everyday need.
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What Is a Length Converter?
A length converter is a tool that instantly translates a measurement expressed in one unit of length into its equivalents in other units — for example, entering 5 feet 10 inches and getting back 1.778 meters, 177.8 centimeters, 70 inches, and 1.944 yards all at once.
Length and distance units fall into two systems: the metric system (millimeters, centimeters, meters, kilometers) used by most of the world, and the imperial/US customary system (inches, feet, yards, miles) used primarily in the United States. Conversions between them arise constantly in everyday life — product dimensions, travel distances, height measurements, construction plans, and athletic race distances.
The foundational conversion is exact by international agreement: 1 inch = 2.54 centimeters exactly. All other conversions derive from this: 1 foot = 30.48 cm exactly; 1 yard = 91.44 cm exactly; 1 mile = 1,609.344 meters exactly. For quick mental math: 1 meter ≈ 3.3 feet; 1 km ≈ 0.6 miles; 1 mile ≈ 1.6 km.
The converter is particularly useful for height conversion (feet/inches to centimeters is extremely common when filling international forms), screen and product dimensions (US manufacturers list in inches; European specs list in centimeters), and running distances (5K = 3.1 miles; 10K = 6.2 miles; marathon = 26.2 miles = 42.2 km).
How to Use the Length Converter
- Enter the value. The number you want to convert.
- Select the source unit. The unit you are converting from.
- Read all conversions. The calculator displays the value in all common units simultaneously — feet, inches, meters, centimeters, millimeters, miles, kilometers, yards.
For height conversion, use the dedicated height mode: enter feet and inches separately to get the exact metric equivalent.
Key Length Conversion Factors
| From | To | Multiply By | |------|-----|------------| | Inches | Centimeters | × 2.54 | | Centimeters | Inches | × 0.3937 | | Feet | Meters | × 0.3048 | | Meters | Feet | × 3.2808 | | Yards | Meters | × 0.9144 | | Meters | Yards | × 1.0936 | | Miles | Kilometers | × 1.6093 | | Kilometers | Miles | × 0.6214 | | Miles | Feet | × 5,280 | | Nautical miles | Kilometers | × 1.852 |
Easy mental approximations:
- 1 meter ≈ 3.3 feet (exact: 3.28)
- 1 km ≈ 0.6 miles (exact: 0.621)
- 1 mile ≈ 1.6 km (exact: 1.609)
- 1 inch = 2.54 cm (exact by definition)
- 1 foot = 30.48 cm (exact by definition)
Common Length Conversion Examples
Height conversions:
| Feet/Inches | Meters | |-------------|--------| | 5'0" | 1.524 m | | 5'6" | 1.676 m | | 5'10" | 1.778 m | | 6'0" | 1.829 m | | 6'4" | 1.930 m |
Distance conversions:
| Miles | Kilometers | |-------|-----------| | 1 | 1.609 | | 5 | 8.047 | | 10 | 16.09 | | 26.2 (marathon) | 42.2 | | 100 | 160.9 |
Screen and product dimensions:
| Inches | Centimeters | |--------|------------| | 6.1" | 15.5 cm | | 11" | 27.9 cm | | 15.6" | 39.6 cm | | 27" | 68.6 cm | | 65" | 165.1 cm |
Frequently Asked Questions
What is the difference between a US mile and a nautical mile? A US (land/statute) mile = 5,280 feet = 1.609 km. A nautical mile = 1,852 meters = 1.151 statute miles. The nautical mile is based on the Earth's circumference — one nautical mile equals one arc-minute of latitude. It is used in aviation and maritime navigation because speed in knots (nautical miles per hour) relates directly to navigation by latitude/longitude.
What is the exact relationship between inches and centimeters? By international agreement (1959), 1 inch = 2.54 centimeters exactly. This is a defined conversion, not a measured approximation — all subsequent conversions (feet, yards, miles) derive from this exact value. Therefore: 1 foot = 30.48 cm exactly; 1 yard = 91.44 cm exactly; 1 mile = 1,609.344 meters exactly.
How do I convert feet and inches to meters? Convert everything to inches first: total inches = (feet × 12) + remaining inches. Then multiply by 0.0254 (since 1 inch = 0.0254 meters exactly). Example: 5 feet 9 inches = (5×12) + 9 = 69 inches × 0.0254 = 1.7526 meters.
What is a millimeter vs. a micrometer vs. a nanometer? 1 millimeter (mm) = 0.001 meters = 1/25.4 inch. 1 micrometer (μm) = 0.000001 meters = 1/1000 of a mm. 1 nanometer (nm) = 0.000000001 meters = 1/1000 of a μm. Context: human hair is 50–100 μm thick; red blood cells are 6–8 μm; visible light wavelengths are 380–700 nm; computer chip features are now below 3 nm.
What length units are used in astronomy? Astronomical distances are too large for kilometers or miles. Astronomers use: Astronomical Unit (AU) = average Earth-Sun distance ≈ 150 million km. Light-year (ly) = distance light travels in one year ≈ 9.46 trillion km. Parsec (pc) = 3.26 light-years, defined by parallax measurement. Kiloparsec (kpc), megaparsec (Mpc) for galaxy-scale distances. The nearest star (Proxima Centauri) is 4.24 light-years away; the observable universe is about 93 billion light-years in diameter.
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The free Length Converter at RoughTools converts between inches, feet, yards, miles, centimeters, meters, kilometers, and nautical miles. Enter one value to see all conversions at once. No account needed, completely free.