About this length converter
Lengths are measured in metric units in most of the world, in feet, inches, yards, and miles in the United States and for many purposes in the UK, in nautical miles at sea and in the air, and in astronomical units and light-years in space. This converter turns any length into all twelve of these units at once, using the exact international definitions, so an inch is exactly 2.54 centimeters and a mile exactly 1,609.344 meters. To make big and small numbers easier to picture, it also compares your length with a person, a football field, a marathon, and distances in the solar system.
How to convert length
- Enter the length. Type a number, or press an example such as 1 mile.
- Choose its unit. Pick the unit the number is in, from micrometers to light-years.
- Press Convert length. Read the length in every unit, copy any value, and check the comparisons and scale.
Frequently asked questions
How many centimeters are in an inch?
Exactly 2.54. Since 1959 the inch has been defined as 25.4 millimeters, so a foot is 30.48 cm and a yard is 91.44 cm.
How do I convert miles to kilometers?
Multiply by 1.609344. Five miles is about 8.05 km. To go from kilometers to miles, multiply by about 0.621371.
What is the difference between a mile and a nautical mile?
A statute mile is 1,609.344 m, while a nautical mile is 1,852 m, based on one minute of latitude. Ships and aircraft use nautical miles and knots.
How far is a light-year?
The distance light travels in a year, about 9.46 trillion kilometers or 63,241 astronomical units. Despite the name, it measures distance, not time.