The Ultimate Guide to Length & Distance Conversion
Master conversions between metric and imperial distance units including meters, feet, inches, miles, and kilometers with exact formulas.
Introduction to Length Measurement
Length is one of the fundamental physical quantities in the International System of Units (SI). While the metric system standardized the meter ($m$) as its primary baseline, the imperial and US customary systems continue to use inches, feet, yards, and miles worldwide.
SI Definition
The meter is defined as the distance traveled by light in a vacuum in exactly 1/299,792,458 of a second.
Common Metric to Imperial Conversion Formulas
The international inch was legally fixed in 1959 to be exactly 25.4 millimeters (or 0.0254 meters).
1 meter is approximately 3 feet and 3.37 inches
For a fast mental calculation, multiply km by 0.6 or use the Fibonacci sequence (3 km ≈ 2 mi, 5 km ≈ 3 mi, 8 km ≈ 5 mi)
Quick Reference Conversion Factors
| From Unit | To Unit | Multiply By | Example |
|---|---|---|---|
| 1 Meter (m) | Feet (ft) | 3.28084 | 10 m = 32.8084 ft |
| 1 Foot (ft) | Centimeters (cm) | 30.48 | 6 ft = 182.88 cm |
| 1 Inch (in) | Centimeters (cm) | 2.54 | 10 in = 25.4 cm |
| 1 Kilometer (km) | Miles (mi) | 0.621371 | 100 km = 62.1371 mi |
| 1 Mile (mi) | Kilometers (km) | 1.609344 | 5 mi = 8.04672 km |
| 1 Nautical Mile (nmi) | Kilometers (km) | 1.852 | 10 nmi = 18.52 km |
Pro Tip for Woodworking & CAD
When working with precision mechanical drawings, always convert inches to millimeters by multiplying by 25.4 to avoid cumulative rounding errors.