Convert Kilometers to Miles
Type any distance in kilometers and get the exact mile equivalent. Useful for marathon training plans, road trip distances and reading maps that mix metric and imperial.
1 km = 0.621371 mi
One kilometer equals 0.621371 miles. To convert kilometers to miles, multiply by 0.621371 — so 10 km = 6.2137 mi and 100 km = 62.137 mi. The international statute mile is defined as exactly 1.609344 km by the 1959 international yard and pound agreement, the same figure used on US road signs, marathon race courses, and vehicle odometers worldwide. Nautical miles used in aviation and shipping are a different unit entirely (1.852 km). Multiplying by 0.6 is accurate to about three percent and enough for reading road signs abroad. The Fibonacci coincidence is a neater trick, since consecutive terms approximate the ratio: 8 km ≈ 5 mi, 13 km ≈ 8 mi and 21 km ≈ 13 mi. Running distances are the most-searched case — 5 km is 3.11 mi, 10 km is 6.21 mi, a half marathon 13.11 mi and a marathon 26.22 mi. Note that a metric mile in athletics means 1,500 m, which is 0.93 statute miles rather than a mile at all.
Quick reference: kilometers to miles
| Kilometers | Miles |
|---|---|
| 1 | 0.621 mi |
| 2 | 1.243 mi |
| 5 | 3.107 mi (5K race) |
| 10 | 6.214 mi (10K race) |
| 15 | 9.321 mi |
| 21.0975 | 13.109 mi (half marathon) |
| 25 | 15.534 mi |
| 42.195 | 26.219 mi (marathon) |
| 50 | 31.069 mi |
| 80 | 49.710 mi |
| 100 | 62.137 mi |
| 160 | 99.419 mi |
| 500 | 310.686 mi |
| 1000 | 621.371 mi |
How do you convert kilometers to miles?
Formula: miles = kilometers × 0.621371 • A marathon (42.195 km) → 42.195 × 0.621371 = 26.2188 mi, the official race distance. • A 100 km/h European motorway speed → 62.14 mph, just above the US 55–65 mph limits. • A 400 km road trip → 248.55 mi, useful when your rental car in Europe shows only kilometers.
When and why people use kilometers to miles
Runners are the biggest audience: race distances are metric worldwide (5 km, 10 km, half marathon, marathon), while US training apps often report pace in minutes per mile. Converting km to miles keeps splits comparable. Drivers hit this every time they cross between metric and imperial road systems. UK motorways use miles even though the country is otherwise metric, Canadian highway signs are in kilometers, and rental cars often display only one unit. Knowing that 100 km/h ≈ 62 mph prevents accidental speeding. Standards note: the international mile has been legally 1609.344 m since 1959, per NIST and the UK NPL. The older US survey mile, 3.2 mm longer, was officially retired for all uses in 2023.
Common mistakes to watch for when converting kilometers to miles
The three usual mistakes: treating a mile as roughly two kilometers (it's 1.6), confusing statute miles with nautical miles (1.852 km, 15 percent longer), and using the 'km × 0.6' shortcut for long distances. On a 1000 km trip the 0.6 shortcut is off by 21 miles. Also watch out for pace conversions. A 5:00 min/km pace is not 8:00 min/mi — it is 8:03 min/mi. The rounding error over a marathon adds up to more than a full minute.
How to estimate kilometers to miles in your head
The reliable trick is to take the kilometre figure, halve it, then add a tenth of the original. For 80 km: half is 40, a tenth is 8, giving 48 miles against a true 49.7 — about 3% low but instant. A more accurate method uses the Fibonacci coincidence: consecutive Fibonacci numbers approximate the km-to-mile ratio. 8 km ≈ 5 mi, 13 km ≈ 8 mi, 21 km ≈ 13 mi, 34 km ≈ 21 mi. These are accurate to within about 0.5%, which is better than most people manage with a calculator under time pressure. For road-sign work, remember that 100 km/h is 62 mph and scale from there. The shortcut breaks down past a few hundred kilometres, where a 3% error becomes tens of miles — use the full 0.621371 factor for anything involving fuel planning or a flight leg.
Kilometers to Miles FAQ
How many miles is 5 km?
- 5 km equals 3.107 miles. It's the classic 5K race distance and takes most walkers 45–60 minutes and most runners 20–35 minutes.
Is 1 km exactly half a mile?
- No. One kilometer is 0.621 miles, not 0.5. The 'half a mile per km' rule of thumb is short by roughly 24 percent per kilometer.
How many miles is a marathon in km?
- A marathon is 42.195 km, which is exactly 26.2188 miles. The race distance was fixed at 26 miles 385 yards at the 1908 London Olympics and later expressed in metric as 42.195 km.
How many km is 100 miles?
- 100 miles equals 160.934 kilometers. Ultra-runners often refer to 100-mile races and 100 km races interchangeably even though the 100-milers are 60 km longer.
What's 60 mph in km/h?
- 60 mph equals 96.56 km/h. That's why European motorways posted at 100 km/h feel about the same as US highways posted at 60 mph.
Is a nautical mile the same as a mile?
- No. A nautical mile is 1.852 km, or 1.1508 statute miles. Aviation, marine navigation and weather forecasts still use nautical miles because they map cleanly to latitude.
How do I estimate km to miles in my head?
- Multiply by 6 and drop a zero. 40 km × 6 = 240, drop the zero → 24 miles (actual 24.85).
Does the conversion differ between the US and UK?
- No. Both countries use the international mile of 1609.344 m, defined by the 1959 international yard and pound agreement.
How many km in a 10-mile race?
- 10 miles is 16.09 km, so a 10-mile race sits between a 15 km and a half marathon.
Last updated:
Sources: 1959 international yard and pound agreement (1 mile = 1609.344 m exactly), NIST Special Publication 811, US National Geodetic Survey retirement of the US survey foot/mile (2023).