Length Converter
Convert between 40+ length units instantly. From Quantum physics to Cosmic scales.
Popular Length Conversions
Length Measurement Facts & History
The meter was originally defined as 1/10,000,000 of the distance from the equator to the North Pole through Paris.
A light-year equals approximately 9.46 trillion kilometers - the distance light travels in one year.
The Planck length (1.616×10⁻³⁵ m) is the smallest length that has any meaning in physics.
One inch was historically defined as the width of a man's thumb, but is now exactly 2.54 centimeters.
The mile comes from the Latin 'mille passus' meaning 'a thousand paces' of a Roman soldier.
At the quantum scale, the very concept of distance becomes uncertain due to Heisenberg's uncertainty principle.
Length Conversion FAQs
How do I convert meters to feet?
Multiply meters by 3.28084. For example, 2 meters = 6.56 feet. For a rough estimate, multiply by 3.3.
Inches to Centimeters?
1 inch is exactly 2.54 cm. This is the global standard for industrial and scientific conversion.
Kilometers vs Miles?
1 mile ≈ 1.61 km. A 5K run is 3.1 miles, and a 10K run is 6.2 miles.
Metric vs Imperial?
The US uses Imperial (Feet/Inches) for construction. The rest of the world and all scientists use Metric (Meters/CM).
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