Convert between millimeters, centimeters, meters, kilometers, inches, feet, yards, miles, micrometers and nanometers with instant multi-unit output and click-to-copy values.
Formula & how it works
All inputs are first normalized to meters (the SI base unit for length), then each target unit is computed using its conversion factor. This avoids chained rounding errors when converting between arbitrary pairs.
Conversion table — common lengths
| m | cm | mm | in | ft | yd |
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Frequently asked questions
How do I convert centimeters to inches?
Divide centimeters by 2.54. One inch is defined as exactly 25.4 millimeters, so 1 cm = 1/2.54 ≈ 0.3937 inches. Example: 180 cm ÷ 2.54 ≈ 70.87 in.
How do I convert feet to meters?
Multiply feet by 0.3048. One international foot is exactly 0.3048 meters by definition. Example: 6 ft × 0.3048 = 1.8288 m.
How many millimeters are in an inch?
Exactly 25.4 mm. That equivalence has been the international definition of the inch since 1959 and is used by all ISO and ANSI standards.
How do I convert kilometers to miles?
Multiply km by 0.621371. One mile equals 1609.344 meters, so 1 km ≈ 0.6214 mi. Example: 10 km × 0.621371 ≈ 6.2137 mi.
What is a micrometer and when is it used?
A micrometer (µm), also called a micron, is one millionth of a meter (10⁻⁶ m). It is used for thin film thickness, optical wavelengths, particle sizes and manufacturing tolerances. 1 µm = 0.001 mm = 10 000 Å.
Why convert everything through meters?
The meter is the SI base unit for length, so it acts as a neutral hub: value × factor(input) = meters, then meters × factor(output) = target. Chaining pair conversions directly would accumulate rounding errors.
This length converter normalizes your input to meters (the SI base unit) and instantly shows the equivalent in nine other units so you can compare metric and imperial at a glance. Enter any value, pick its unit, and every card below updates in place — click a card to copy its number to the clipboard. Supported units: mm, cm, m, km, inch, foot, yard, mile, micrometer and nanometer. The formula panel shows the exact conversion factors used. Examples: 1 meter equals 3.2808 feet or 39.3701 inches; 6 feet equals 1.8288 m or 182.88 cm; 100 km equals 62.1371 miles. The reference table below lists common benchmarks from 1 mm up to 1 km across all major units.