km to miles Converter
Convert km to miles instantly with a reference conversion table.
| km | miles |
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How to convert km to miles
Enter your value
Type the number of km you want to convert into the left box. The result in miles appears instantly in the right box. You can also type into the right box to convert in the other direction.
Use the swap button
Click the ⇄ Swap button to reverse the conversion — miles to km. Your current value carries across so you don't have to re-enter anything.
About km and miles
The kilometre is the standard unit of distance in the metric system, used for road signs, race distances and everyday measurement across almost every country in the world. The mile has a much older history — it comes from the Roman "mille passus" ("a thousand paces"), later standardised in England to exactly 1,760 yards, or 1,609.344 metres. That fixed-metre definition is what today's conversion factor is built on: since 1 mile = 1,609.344 metres exactly, 1 km = 1 ÷ 1.609344 = 0.621371 miles, to six decimal places. It's not a rounded approximation — it's an exact ratio derived from the international agreement that standardised the yard and the mile in metric terms back in 1959.
Km to miles for runners and drivers
This conversion comes up constantly for two groups in particular: distance runners and anyone driving in a country that uses the other unit. A few reference points that come up often enough to be worth memorising:
Running distances
A 5K is 3.107 miles, a 10K is 6.214 miles, a half marathon (21.0975 km) is 13.1 miles, and a full marathon (42.195 km) is 26.219 miles — the famous "26.2." Parkrun's 5km course is the same 3.107-mile distance worldwide, which is why UK and US runners quote the same event in different units without it being a different race.
Road speeds and distances
UK motorway speed limits (70mph) equal roughly 113 km/h; a 30mph residential limit is about 48 km/h. Renting a car in continental Europe with a speedometer marked only in km/h, or driving in the UK/US with one marked only in mph, is the single most common reason people search this conversion mid-trip.
Quick mental-math shortcut
For a rough estimate without a calculator: halve the kilometre figure, then add 10% of the original number. 100 km → 50 + 10 = 60 (exact answer: 62.14) — close enough for trip planning, though the exact figure above is what to use for anything that matters, like fuel calculations or pace targets.
Why does the UK still use miles?
The UK began a formal metrication programme in 1965, and today most UK measurements — weight, volume, most distances in industry and science — are metric. Road signage is the visible exception: distances and speed limits are still shown in miles and mph, a decision that has stuck largely because of the cost and safety risk of replacing every road sign in the country at once, not because of any technical preference for the mile. Ireland, by contrast, converted its road signs from miles to kilometres in January 2005. The United States never adopted metric for everyday use at all, so miles remain the default there for driving, running events, and most casual distance measurement. Nearly every other country — including the rest of Europe, Australia, and Canada — uses kilometres exclusively for road distances, which is why this specific conversion is one of the most searched on the site.
Frequently asked questions
How do I convert km to miles?
To convert km to miles, multiply by 0.621371. Or use the calculator above for instant results.
How many miles are in 1 km?
1 km equals 0.621371 miles.
Is the km to miles converter free?
Yes, the km to miles converter is completely free with no sign-up required, no downloads, and it works offline once the page has loaded.
How many km is a marathon in miles?
A marathon is 42.195 km, which equals 26.219 miles — commonly rounded to 26.2 miles.
Is a kilometre longer or shorter than a mile?
A kilometre is shorter than a mile. 1 mile equals 1.609344 km, so it takes about 1.6 kilometres to cover the same distance as one mile.
Why does the UK use miles instead of kilometres?
The UK metricated most measurements from 1965 onwards, but road signage was left in miles due to the cost and safety risk of replacing every sign nationwide. Most other countries, including Ireland since 2005, use kilometres for road distances.
1 km ≈ 0.621 miles. A common shortcut: half the kilometres and add 10% — close enough for road trips. 100 km ≈ 62 miles (exact 62.137).
| km | miles |
|---|---|
| 0.1 | 0.06214 |
| 0.5 | 0.3107 |
| 1 | 0.6214 |
| 2 | 1.243 |
| 5 | 3.107 |
| 10 | 6.214 |