The SI base unit is the meter (m). Enter a value to convert across all units.
Enter a value to convert across all units.
Length Conversion Guide
Metric System
The metric system is based on powers of 10. The meter is the base unit. Prefixes like kilo- (1000), centi- (1/100), and milli- (1/1000) denote multiples and fractions.
Imperial System
Widely used in the US and the UK. A foot is exactly 12 inches, a yard is 3 feet, and a mile is 1,760 yards (5,280 feet). A "mil" (or thou) is 1/1000 of an inch, common in engineering and manufacturing.
Key Conversion Factors
| Metric to Metric | Imperial to Imperial | Metric to Imperial |
|---|---|---|
| 1 m = 100 cm = 1000 mm | 1 ft = 12 in | 1 in = 2.54 cm |
| 1 km = 1000 m | 1 yd = 3 ft = 36 in | 1 ft = 30.48 cm |
| 1 mm = 1000 μm = 1,000,000 nm | 1 mi = 1760 yd = 5280 ft | 1 yd = 0.9144 m |
| 1 cm = 10 mm | 1 in = 1000 mil | 1 mi ≈ 1.609 km |
Frequently Asked Questions
How many centimeters are in an inch?
Exactly 2.54 centimeters equal 1 inch. This is the exact definition used internationally.
What is a "mil"?
A mil, also known as a thou, is one-thousandth of an inch (0.001 inches). It is commonly used in manufacturing, machining, and specifying the thickness of materials like plastic films or PCB traces.
How many feet are in a meter?
One meter is approximately 3.28084 feet. For a rough estimate, you can multiply meters by 3.3.