About this tool
Why use this tool
Converting between miles, kilometers, feet and meters is essential for international travel, reading foreign maps, running with training apps that use metric splits, and interpreting scientific data. The US is one of only three countries (with Liberia and Myanmar) that has not officially adopted the metric system, though NASA, science and medicine use SI daily. NIST maintains the US customary system's exact conversions.
How it works
1 mile = 1.609344 km exactly (International Yard and Pound Agreement 1959). 1 km = 0.621371 miles. 1 foot = 0.3048 m; 1 meter = 3.28084 ft. The nautical mile used in aviation/maritime = 1.852 km (based on 1 minute of latitude). The US survey mile differs by 3.2 mm/mile — usually ignored outside land surveying.
Real example
A marathon is 26.2188 miles or 42.195 km. A 60 mph highway speed = 96.56 km/h. A cross-country flight from LAX to JFK covers about 2,475 miles or 3,983 km (or 2,151 nautical miles). A football field goal-to-goal is 120 yards = 109.7 m.
Practical tips
For quick mental math: multiply km by 0.6 to get miles roughly (100 km ≈ 60 miles). To go from miles to km, multiply by 1.6 (60 miles ≈ 96 km). Runners: 5K = 3.1 miles, 10K = 6.2 miles, half-marathon = 13.1 miles. Rental cars in Europe display km/h — a 130 km/h autobahn zone is about 80 mph. Google Maps, Strava and Garmin let you toggle units in settings. NOAA and FAA publish nautical charts in nautical miles; general aviation students should master both.
Disclaimer
Conversions here follow NIST's exact ratios. For high-precision surveying use the US Survey Foot (differs by 2 ppm). Maritime and aviation applications must use nautical miles. This tool is for general reference and not for engineering, surveying or navigation-grade calculations.