An American driver crossing into Canada meets the moment that makes this page necessary: the speedometer still reads in miles per hour, but every sign now speaks kilometers per hour, and 100 on the sign is not permission to cruise at 100 mph — it is 62.14. The exchange rate between the two distance units is exact and worth memorizing: one mile equals 1.60934 kilometers, so miles × 1.60934 gives kilometers, and the reverse trip multiplies kilometers by 0.621371 to get miles. One mile is also 1,609.34 meters and the familiar 5,280 feet, which is why the Meters (m) and Feet (ft) boxes ride along on this page — one entry answers the road sign, the hiking map, and the science homework at once.

Start with the headline worked example: 100 miles × 1.60934 = 160.934 kilometers, the number on every international road sign marking a century drive. A marathon's 26.2 miles becomes 42.1648 km — the readout rounds to 42.165, essentially the famous 42.195 km race distance. A half-marathon's 13.1 miles becomes 21.0824 km. Type 60 into the Miles (mi) box and you will see about 96.56 km, the conversion behind every "miles to km" question asked at a rental-car counter in Europe.

Mental-math tricks that survive the highway.

The everyday estimate is ×1.6: 70 mph becomes about 112 km/h, within half a percent of the exact 112.65. For a slightly better mental trick, double the miles and subtract 20 percent of the doubled number — 50 miles doubles to 100, minus 20 gives 80, against the exact 80.467. That trick works because doubling is multiplication by 2 and the subtraction corrects most of the gap between 2 and 1.60934. Going the other way, kilometers to miles, multiply by 0.62: 100 km becomes about 62 miles, against the exact 62.14. None of these replace the converter for precise work, but they keep you legal on a foreign highway when the phone is in the glove box.

The schoolroom anchor is even simpler: 5 miles is about 8 kilometers — 8.0467, to be precise. From that one pair you can bootstrap most distances: 10 miles is about 16 km, 25 miles is about 40 km, 50 miles is about 80 km, and each is within a fraction of a percent of exact. It is the same trick track coaches use when a runner's watch flips to metric mid-season, and the same pair that appears on classroom worksheets from Ohio to Ontario.

Speed limits, translated.

Miles per hour and kilometers per hour convert with the same 1.60934 factor, because speed is just distance over time. Common US highway speeds: 55 mph is 88.51 km/h, 65 mph is 104.61 km/h, 70 mph is 112.65 km/h, 75 mph is 120.70 km/h, and 80 mph is 128.75 km/h. City speeds: 25 mph is 40.23 km/h, 35 mph is 56.33 km/h, 45 mph is 72.42 km/h. Crossing the border the other way, read the signs with ×0.621371: a 50 km/h city limit is 31.07 mph, a 100 km/h highway is 62.14 mph, and a 120 km/h freeway is 74.56 mph. Cruise control set by feel in a rental car is how tourists collect tickets; the math takes five seconds.

Running: miles, kilometers, and race distances.

Runners live at the intersection of both systems. A 5K is 5 kilometers, which is 3.1069 miles; a 10K is 6.2137 miles. The marathon's 42.195 km converts to 26.2187 miles — the famous 26.2. An ultramarathon's 100 miles is 160.934 km, and Europe's legendary UTMB course at 176.4 km is 109.61 miles. Cyclists have their own version: an American "century ride" is 100 miles (160.934 km), while a European metric century is 100 km — just 62.14 miles, a noticeably shorter day in the saddle. When a training plan written in Europe meets an American GPS watch, the 1.60934 factor keeps every workout honest.

Pace is where runners get tripped up: minutes per mile and minutes per kilometer are not interchangeable. A 6:00-per-mile marathon pace is 3:44 per kilometer, an 8:00-per-mile training pace is 4:58 per kilometer, and a 10:00-per-mile easy pace is 6:13 per kilometer. Divide the per-mile pace by 1.60934 to get the per-kilometer pace. Strava friendships across the Atlantic founder on exactly this confusion — a 5:00/km run looks slow to an American until you convert it to 8:03 per mile.

Road trips and real distances.

The classic American road trips convert cleanly: New York to Boston is about 215 miles, or 346.01 km. Los Angeles to San Francisco is about 382 miles, or 614.77 km. New York to Chicago is about 790 miles, or 1,271.38 km. A full coast-to-coast drive of roughly 2,800 miles is about 4,506.16 km — the number that makes European visitors blink, since it is farther than Lisbon to Moscow. Flying stretches the same factor: New York to London is about 3,459 miles, or 5,566.72 km. And for a sense of cosmic scale, the Moon sits about 238,855 miles away, which is 384,399.86 km — essentially the textbook 384,400 km figure.

The reverse ladder: kilometers back to miles.

The searches run both directions, so keep the reverse anchors handy: 100 km is 62.14 miles, 150 km is 93.21 miles, 200 km is 124.27 miles, 300 km is 186.41 miles, and 500 km is 310.69 miles. A European car's "500 km range" sticker means about 311 miles of driving. France's TGV at 300 km/h is doing 186.41 mph, and Japan's Shinkansen at 320 km/h is 198.84 mph. The exact move is kilometers × 0.621371, and the mental shortcut is multiply by 0.62, which undershoots by less than half a percent.

Fuel economy: the conversion drivers actually need.

American fuel economy is miles per gallon; the rest of the world is liters per 100 km, and the two scales run in opposite directions — bigger mpg is better, smaller L/100km is better. The bridge is 235.214 divided by mpg: 30 mpg is 7.84 L/100km, 25 mpg is 9.41 L/100km, and 40 mpg is 5.88 L/100km. A European rental quoting 6.5 L/100km is delivering about 36.2 mpg — 235.214 ÷ 6.5. When the rental agent brags about efficiency in liters and your brain budgets in gallons, this one division translates the brag into dollars.

Why the mile is 5,280 feet, and why America kept it.

The mile descends from the Roman mille passus — a thousand paces, about 5,000 Roman feet. In 1593, Queen Elizabeth I fixed the statute mile at 5,280 feet, or eight furlongs, partly so the mile would divide evenly into the furlong-based surveying system. The kilometer arrived two centuries later with the French metric system: 1,000 meters, no history attached, pure decimal logic. When the US Metric Conversion Act of 1975 made metric use voluntary rather than mandatory, road signs, speedometers, and odometers stayed in miles — and they have stayed ever since, making the US one of the few countries where drivers still think in miles.

For students, hikers, and the curious.

A mile is 5,280 feet and 1,609.34 meters — the Feet and Meters boxes on this page show both alongside the kilometer headline, which is exactly what a hiking map's mixed units or a physics problem set demands. Teachers use the 8 km ≈ 5 mile anchor for estimation exercises and the exact factor for the real thing. One caution: pilots and sailors use a different mile entirely — the nautical mile is 1.852 km — so if an aviation chart looks wrong, check the unit before blaming the math. And a light-year is about 5.879 trillion miles, or 9.461 trillion km; the factor scales to the stars unchanged.

Precision: when 1.6 is enough and when it isn't.

For driving and estimating, 1.6 is fine — the error is under 0.6 percent, about half a kilometer on a hundred. For engineering, surveying, and scientific work, use the full 1.60934 and round only at the end. The Kilometers readout on this page carries four decimals, the Meters box one, and the Feet box one — precision where it counts, readability everywhere else. The rule mirrors every converter on this site: estimate with the short factor, build with the exact one.

Odometers, trip computers, and the rental-car dashboard.

A European rental car's dashboard speaks only kilometers: the odometer, the remaining-range estimate, and the trip computer all run in km. When the fuel light comes on with "80 km range," that is 49.71 miles to find a station — 80 × 0.621371. Cruise control set to 130 on a French autoroute is 80.78 mph, which is why the ticket arrives. Hikers meet the same conversion on the trail: the Appalachian Trail's roughly 2,200 miles is about 3,540.55 km, and a Grand Canyon rim-to-rim hike of 24 miles is 38.62 km. Trail guides in metric countries quote elevation gain in meters too — which is exactly why the Meters and Feet boxes sit beside the kilometer headline on this page.

Drop any distance into the Miles (mi) box and the Kilometers (km), Meters (m), and Feet (ft) readouts update together. Whether it is a speed limit abroad, a race distance, a road trip, or a homework problem, the math is one multiplication by 1.60934 — the exact bridge between the American mile and the rest of the world's kilometer.

With the pre-filled defaults — Miles (mi) 100 — the Miles to Kilometers returns Kilometers (km) 160.9340, Meters (m) 160,934.0, Feet (ft) 528,000.0. Change any input and those results update instantly, so you can see exactly how each number you enter moves the answer.