About this tool
Why use this tool
Britain lives in a curious dual system: distances on road signs are in miles, but the OS grid, sport (100 m sprint), science and most weather forecasts use kilometres and metres. Converting between miles, km, feet and metres matters for international travel, marathon training on foreign apps, buying a car imported from the EU with a km/h speedometer, and reading Ordnance Survey maps at 1:25,000 metric scale.
How it works
1 mile = 1.609344 km (1959 International Yard and Pound Agreement, adopted by the UK). 1 km = 0.621371 miles. 1 foot = 0.3048 m; 1 metre = 3.28084 feet. The nautical mile used by the RAF, Royal Navy and merchant shipping = 1.852 km. UK statute laws (Weights and Measures Act 1985) still recognise imperial units for road distances and draught beer.
Real example
A London Marathon covers 26.219 miles or 42.195 km. The M25 motorway is 117 miles or 188 km long. A UK 70 mph motorway limit = 112.7 km/h. The Snowdon summit is 1,085 m or 3,560 ft high. Land's End to John o' Groats by road: 874 miles or 1,407 km.
Practical tips
For quick mental conversion, multiply km by 5 and divide by 8 (or km × 0.6 ≈ miles). Runners: parkrun 5K = 3.1 miles. When driving in France or Spain, remember the speed limit shift — 130 km/h motorway = 80 mph. On OS Explorer maps 4 cm = 1 km (1:25,000). Set your Garmin or Strava app to your preferred unit — many British runners keep pace in min/km for consistency with training plans. The Met Office reports in mph for wind (and km/h in metric conversions).
Disclaimer
Conversions here use NPL-endorsed exact ratios. For maritime navigation always use nautical miles. Ordnance Survey grid references are in metres and never in feet. This tool is for general reference only, not for professional surveying or navigation.