Length conversion comes up constantly when mixing metric and imperial measurements — reading a recipe, following a home improvement plan, or comparing product dimensions across countries. This converter handles the eight most common length units, using meters as the internal reference point for accuracy.
Conversion factors used
| Unit | Meters equivalent |
|---|---|
| 1 millimeter (mm) | 0.001 m |
| 1 centimeter (cm) | 0.01 m |
| 1 kilometer (km) | 1,000 m |
| 1 inch (in) | 0.0254 m |
| 1 foot (ft) | 0.3048 m |
| 1 yard (yd) | 0.9144 m |
| 1 mile (mi) | 1,609.344 m |
How the conversion works
To convert 1 meter to feet: 1 × 1 = 1 meter, then 1 ÷ 0.3048 ≈ 3.28084 feet. Routing every conversion through meters as a common reference keeps the logic simple and avoids needing a separate formula for every possible unit pair.
Worked examples
| From | To | Result |
|---|---|---|
| 10 km | miles | 6.21 mi |
| 5 ft | cm | 152.4 cm |
| 36 in | yards | 1 yd |
Common mistakes
- Confusing US and UK measurement conventions. Most everyday length units (inches, feet, miles) are the same in both systems, but always double-check for specialized units that can differ.
- Rounding too early. When converting through several steps, keep full precision until the final result to avoid compounding rounding errors.
References
- National Institute of Standards and Technology (NIST) — official US customary and metric unit definitions
Frequently asked questions
How many centimeters are in an inch?
One inch equals exactly 2.54 centimeters, by international agreement since 1959.
How do I convert meters to feet?
Multiply the number of meters by approximately 3.28084 to get feet.
Is a mile longer than a kilometer?
Yes. One mile equals approximately 1.60934 kilometers, so a mile is about 60% longer than a kilometer.