About the Length Converter
The Length Converter turns any length or distance into another unit: inches to centimeters, feet to meters, miles to kilometers and back. Type a number, pick the two units, and the result appears right away, together with the same length in all 21 units the tool knows.
It is useful for home projects with metric plans, travel distances abroad, running and cycling routes, sewing and crafts, shipping dimensions, and science or engineering work. Besides the common units, it includes mils for thin materials, nautical miles for boats and planes, older units like fathoms, chains and furlongs, and astronomical distances.
Every factor uses the exact international definition: an inch is exactly 2.54 centimeters, a foot exactly 0.3048 meters and a mile exactly 1,609.344 meters. Everything runs in your browser.
How to use it
- Enter a lengthType the number in the From box. Decimals work, so 5.5 feet or 0.75 inches is fine.
- Pick the unitsChoose the From and To units. Common pairs like Meters → Feet and Centimeters → Inches are one click away.
- Swap if neededClick the swap button between the boxes to reverse the direction.
- Read the factorThe line under the boxes shows what to multiply by, such as "Inches to centimeters: multiply by 2.54".
- See every unit and copyThe list below shows the length in all 21 units. Choose the precision and copy any value.
Key features
21 length units
Metric from nanometers to kilometers, US units from mils to miles, nautical miles, traditional units and astronomical distances.
Exact definitions
Inch, foot, yard and mile use the international definitions agreed in 1959, which are exact in meters.
All units at once
One value fills the whole list, handy when a form or a drawing needs several units.
Precision you choose
4, 6, 10 or 15 significant digits, with scientific notation for very large and very small lengths.
Reusable factor
The multiply-by factor is shown for every pair, so you can convert a whole column in a spreadsheet.
Private by design
No account and no upload. Everything is calculated on your device.
Examples
Around the house
| From | To |
|---|---|
| 1 inch | 2.54 centimeters |
| 8.5 inches | 215.9 millimeters |
| 11 inches | 279.4 millimeters |
| 6 feet | 1.8288 meters |
| 1 meter | 3.280839895 feet |
| 100 yards | 91.44 meters |
A US letter sheet is 8.5 × 11 inches, which is 215.9 × 279.4 mm. A football field of 100 yards between the goal lines is 91.44 meters.
Heights in feet and inches
The converter takes one unit at a time, so turn a height into inches first: 5 feet 10 inches is 5 × 12 + 10 = 70 inches, and 70 inches is 177.8 centimeters. You can also use decimal feet: 5.5 feet (5 feet 6 inches) is 167.64 cm.
Running and travel
| From | To |
|---|---|
| 5 kilometers | 3.106855961 miles |
| 26.2 miles | 42.1648128 kilometers |
| 42.195 kilometers | 26.21875746 miles |
| 1 mile | 5,280 feet |
| 1 nautical mile | 1.852 kilometers |
The official marathon is 42.195 km, slightly more than the 26.2 miles people usually quote. Nautical miles are used at sea and in the air because one nautical mile is about one minute of latitude.
Old and unusual units
| Unit | Equals |
|---|---|
| 1 hand | 4 inches |
| 1 fathom | 6 feet |
| 1 chain | 66 feet |
| 1 furlong | 220 yards |
| 1 league | 3 miles |
| 1 mil (thou) | 0.0254 millimeters |
Hands measure horses, fathoms water depth, furlongs horse races, and mils the thickness of plastic sheeting and coatings. A mil is a thousandth of an inch, not a millimeter.
Very large and very small
One light year is 9.460730473 × 10¹⁵ meters, or about 5,878,625,373,000 miles, and one parsec is 3.261563777 light years. At the other end, 1 nanometer is 1 × 10⁻⁹ meters, and 0.1 nanometers is exactly 1 ångström.
Tips
- For quick estimates, 1 inch is about 2.5 cm, 1 foot about 30 cm, 1 meter about 3.3 feet, and 1 mile about 1.6 km.
- Convert feet and inches to inches before you start (feet × 12 + inches). It is the easiest way to get an exact metric height.
- Use the 4-digit precision setting for carpentry and sewing. Nobody can cut to a hundred-thousandth of a millimeter.
- When ordering materials, round in the safe direction: up for lengths you need to cover, down for space you need to fit into.
- For areas and volumes, such as square feet or cubic meters, use the Unit Converter. Squaring a length factor by hand is a common source of errors.
Common mistakes and limits
- Typing 5.10 for 5 feet 10 inchesDecimal feet are not feet and inches: 5.10 feet is 5 feet 1.2 inches. Use 70 inches or 5.8333 feet instead.
- Confusing mils with millimetersA mil is a thousandth of an inch, 0.0254 mm. A 6-mil plastic sheet is about 0.15 mm thick, not 6 mm.
- Using statute miles at seaA nautical mile is 1.852 km, about 15% longer than a regular mile. Boat and flight speeds in knots are nautical miles per hour.
- Converting areas with length factorsOne meter is 3.28 feet, but one square meter is 10.76 square feet. Use the Area category of the Unit Converter for that.
- Expecting the old US survey footThe tool uses the international foot of exactly 0.3048 m. The slightly longer US survey foot was retired at the end of 2022, apart from older land records.