How to Convert Kilometres to Miles
Kilometres and miles are the two units most people reach for when measuring distance. If you travel between countries, follow international sports, read foreign news or use mapping apps, you will regularly need to switch between them.
This guide gives you the formulas, the shortcuts and the conversion table you need. For instant results at any time, use the free Length Converter on CalConvs.
The Relationship Between Kilometres and Miles
One kilometre is exactly 0.621371 miles. One mile is exactly 1.60934 kilometres. These are the precise conversion factors used in science and navigation.
The kilometre is part of the metric system and is used in almost every country in the world. The mile is part of the imperial system and is used primarily in the United States and the United Kingdom for road distances.
The Exact Conversion Formulas
Kilometres to miles: Miles = Kilometres multiplied by 0.621371
Miles to kilometres: Kilometres = Miles multiplied by 1.60934
Example 1: Convert 10 km to Miles
10 multiplied by 0.621371 = 6.214 miles
Example 2: Convert 26.2 Miles to Kilometres (a Marathon)
26.2 multiplied by 1.60934 = 42.164 km
Quick Mental Maths Shortcuts
You do not always need an exact answer. For everyday estimates, these shortcuts are accurate enough.
Kilometres to miles: Multiply by 0.6 (or divide by 1.6)
Miles to kilometres: Multiply by 1.6 (or divide by 0.6)
Mental Shortcut: How Far Is 50 km in Miles?
50 multiplied by 0.6 = 30 miles (exact answer is 31.07 miles)
The Fibonacci shortcut: consecutive Fibonacci numbers give close approximations. 5 km is approximately 3 miles. 8 km is approximately 5 miles. 13 km is approximately 8 miles.
Kilometres to Miles Conversion Table
| Kilometres | Miles | Context |
|---|---|---|
| 1 km | 0.621 miles | About half a mile plus a bit |
| 5 km | 3.107 miles | Standard 5K race distance |
| 10 km | 6.214 miles | Standard 10K race distance |
| 21.1 km | 13.1 miles | Half marathon distance |
| 42.195 km | 26.219 miles | Full marathon distance |
| 50 km | 31.069 miles | Common cycling event distance |
| 100 km | 62.137 miles | Ultra running distance |
| 1 mile | 1.609 km | Standard mile run |
| 5 miles | 8.047 km | Common running route |
| 26.2 miles | 42.164 km | Marathon in miles |
| 60 mph | 96.56 km/h | Common highway speed limit in miles |
| 100 km/h | 62.14 mph | Common highway speed limit in km |
Speed Conversion: km/h to mph
The same conversion factors apply to speed. Kilometres per hour to miles per hour uses exactly the same arithmetic.
| km/h | mph |
|---|---|
| 30 km/h | 18.6 mph (typical residential speed limit) |
| 50 km/h | 31.1 mph (common urban speed limit) |
| 80 km/h | 49.7 mph (common rural speed limit) |
| 100 km/h | 62.1 mph (common highway speed limit) |
| 110 km/h | 68.4 mph (European motorway limit) |
| 120 km/h | 74.6 mph (common European highway limit) |
Use the Speed Converter for any km/h to mph calculation, including knots and metres per second.
Distance Conversion for Common Activities
| Walking 1 mile | Takes about 15 to 20 minutes for most people. Equal to 1.609 km. |
| Running a 5K | 5 kilometres equals 3.107 miles. A common beginner race distance. |
| Cycling 10 miles | Equal to 16.09 km. A moderate cycling outing. |
| Driving 100 miles | Equal to 160.93 km. About 1.5 to 2 hours on a highway. |
| Flying 1,000 km | Equal to 621.4 miles. Roughly London to Edinburgh and back. |
Why Two Systems Still Exist
The metric system is the international standard and is used in virtually every country for science, medicine and official measurement. However, the United States, United Kingdom, Myanmar and a small number of other countries still use miles for road distances in everyday life.
In the UK, road signs show miles and speed limits are in mph, but the metric system is used in science, medicine and most commercial settings. This is why British people fluently switch between both systems depending on context.
Related Tools
- Length Converter for km to miles and 70 or more other length units
- Speed Converter for km/h to mph, knots and metres per second
- All Unit Converters browse all 74 converters on CalConvs
Frequently Asked Questions
How do I convert kilometres to miles in my head?
Multiply the kilometres by 0.6 for a quick estimate. So 10 km is about 6 miles and 50 km is about 30 miles. For more precision, use consecutive Fibonacci numbers: 5 km is almost exactly 3 miles, 8 km is about 5 miles, and 13 km is about 8 miles. These pairs work because the ratio of consecutive Fibonacci numbers is close to the mile to kilometre conversion factor.
What is 100 km in miles?
100 km is equal to 62.137 miles. As a quick mental estimate, multiply by 0.6 to get 60 miles, the exact answer is about 3.5 percent higher. The same conversion applies to speed: 100 km/h equals 62.14 mph.
Why does the UK still use miles instead of kilometres?
The UK adopted the metric system for most commercial and scientific purposes but retained miles for road distances through historical convention and public familiarity. Changing all UK road signs has been estimated to cost over a billion pounds. British people regularly switch between both systems, miles for roads, but kilograms and litres in supermarkets.
What is the difference between a mile and a nautical mile?
A standard land mile (statute mile) is 1,609.344 metres. A nautical mile is 1,852 metres, about 15 percent longer. Nautical miles are used in aviation and maritime navigation because one nautical mile equals one minute of latitude on the Earth's surface. A knot is one nautical mile per hour.