Length Converter
Convert any length or distance between metric and imperial units. Enter one value and see it in all eight units simultaneously — meters, kilometers, centimeters, millimeters, miles, yards, feet and inches.
How to use this calculator
- Enter the value you want to convert.
- Choose the unit you're converting from and to.
- Press Convert — the result appears first, followed by your value in every other unit.
Formula used
All conversions go through meters as the base unit: result = value × (from-factor ÷ to-factor). The inch is defined as exactly 2.54 cm, which anchors the entire imperial-metric relationship.
Example calculation
Convert 100 cm to inches: 100 × 0.01 m ÷ 0.0254 = 39.37 inches — or about 3 feet 3.4 inches.
Metric vs imperial length
The metric system scales by tens (mm → cm → m → km), while imperial units evolved from body measurements: 12 inches to a foot, 3 feet to a yard, 1,760 yards to a mile. Since 1959, the two systems are locked together by definition: 1 inch = exactly 2.54 cm.
The conversions worth memorizing: 1 inch ≈ 2.5 cm, 1 foot ≈ 30 cm, 1 meter ≈ 3.3 feet, 1 mile ≈ 1.6 km, and 1 km ≈ 0.62 miles.
Why use this calculator?
- See every unit at once instead of converting pair by pair.
- Exact defined factors — no rounded approximations compounding into errors.
- Works for heights, room sizes, running distances, screen sizes and shipping dimensions alike.
Frequently asked questions
How many feet are in a meter?
1 meter = 3.28084 feet, or about 3 feet 3⅜ inches. To convert meters to feet quickly, multiply by 3.28; for feet to meters, multiply by 0.3048.
How many cm is an inch?
Exactly 2.54 cm — this is a defined value, not a measurement. So 10 cm ≈ 3.94 inches and 30 cm is very close to 1 foot (30.48 cm).
How do I convert miles to kilometers in my head?
Multiply by 1.6 (or add 60%): 10 miles ≈ 16 km. Going the other way, multiply km by 0.6: 100 km ≈ 62 miles. Runners' shortcut: a 5K is about 3.1 miles.