Convert mi to km miles ↔ kilometres Free Online Secure
Type a value in miles and read it in kilometres at once. The factor is exact by definition, the arithmetic happens in your browser, and nothing is sent anywhere.
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Common values — Convert mi to km (miles ↔ kilometres)
| mi | km |
|---|---|
| 1 | 1.609344 |
| 2 | 3.218688 |
| 3 | 4.828032 |
| 5 | 8.04672 |
| 10 | 16.09344 |
| 20 | 32.18688 |
| 50 | 80.4672 |
| 100 | 160.9344 |
Where these units come from
The metre was first defined in 1793 as a ten-millionth of the distance from the equator to the North Pole — a definition nobody could check without surveying a quarter of the planet. It has been redefined four times since, each time to something steadier: a platinum bar, then a prototype kept in Paris, then a wavelength of krypton light, and since 1983 the distance light travels in vacuum in 1/299,792,458 of a second. The inch stopped being a separate thing in 1959, when six countries agreed to define it as exactly 25.4 mm. That agreement is why every conversion on this page between a metric and an imperial length is exact rather than measured: both sides now descend from the same definition.
Where you meet them
Millimetres are the working unit of engineering drawings and of anything made in a workshop; centimetres belong to tailoring, furniture and school rulers; metres to rooms, fabric and running tracks. Feet and inches survive in aviation altitudes worldwide, in American and British construction, and in the diagonal of every screen you have ever bought. Nautical miles are not a quaint survival — one is a minute of latitude, which is why ships and aircraft still navigate in them.
Questions people ask
Is a mile the same everywhere?
The statute mile on this page is 1609.344 m exactly, which follows from the 1959 inch. The nautical mile is a different unit altogether, 1852 m exactly, defined as one minute of arc along a meridian. The two are not variants of one another and should never be swapped.
Which countries still measure road distances in miles?
The United States and the United Kingdom, where road signs show miles, together with a handful of smaller countries such as Liberia and Myanmar. Almost everywhere else road distances are in kilometres. One kilometre is 1000 metres and about 0.621 of a mile, so a distance in miles is about five-eighths of the same distance in kilometres.
Is the answer exact?
Where both units are defined in terms of one another by whole numbers, yes — the page says so above the figure, and the only rounding is in how many digits are shown. Where the ratio has no finite decimal, the page shows twelve significant digits and says the relation is approximate rather than pretending otherwise.
Does anything I type leave my device?
No. The arithmetic runs in your browser; nothing is uploaded and there is no server to upload it to. Load the page once and it keeps working with the network switched off.
Sixty miles an hour in a metric head: how to convert mi to km
Rent a car in California and the speed limit says 65. Read a guide to Scotland and the next village is 12 miles away. Follow an American marathon plan and the long run is 18 miles. If you think in kilometres, none of these numbers means much until you convert mi to km, and this page does it the moment you type the figure. Enter miles, read kilometres, as many decimals as you like.
The conversion factor is 1.609344, exact because the mile is defined as 1,609.344 metres. That is awkward to remember, but there are several nice shortcuts, one of which uses the Fibonacci sequence. The sections below give the rule, worked examples, a profile of each unit, a comparison, a tour of the places where the conversion appears, and a list of the mistakes people make.
How to convert mi to km: multiply by 1.609344
The rule
One mile is exactly 1.609344 km. To convert mi to km, multiply the number of miles by 1.609344. 1 mi is 1.609 km, 5 mi is 8.047 km, 10 mi is 16.09 km, 26.2 mi is 42.16 km and 100 mi is 160.9 km. In the other direction, divide kilometres by 1.609344, or multiply by 0.621371.
Worked examples
The speed limit of 65 mph is 104.6 km/h. A drive of 240 mi is 386 km. A marathon, 26.219 mi, is 42.195 km. A half marathon, 13.109 mi, is 21.0975 km. A 5 mile run is 8.05 km. A flight of 3,000 mi is 4,828 km.
Mental tricks
For a mental convert mi to km, multiply by 8 and divide by 5: 50 mi times 8 is 400, divided by 5 is 80 km, against the exact 80.5. Or add 60 per cent: 50 plus 30 is 80. Another trick uses the Fibonacci numbers 1, 2, 3, 5, 8, 13, 21, 34, 55, 89. Each number is roughly the next one in kilometres when it stands for miles: 5 mi is 8 km, 8 mi is 13 km, 13 mi is 21 km, 21 mi is 34 km.
Why the trick works
The ratio of consecutive Fibonacci numbers approaches 1.618, the golden ratio, which is within 0.5 per cent of 1.609. That is why a pair of neighbours in the sequence is a good conversion.
The mile
A thousand paces
The statute mile is 5,280 feet, 1,760 yards and exactly 1,609.344 m. It comes from the Roman thousand paces and was fixed in England in 1593. It is the road unit of the United States and the United Kingdom.
Mile in culture
The mile appears in speed limits, fuel economy, running events and in songs from "500 Miles" to "Walk a Mile in My Shoes". Americans think of the world in miles: the Appalachian Trail is 2,190 mi long, Route 66 2,448 mi.
The kilometre
A thousand metres
The kilometre is the road unit of nearly all the world. The name combines the Greek kilo, a thousand, and metre. Its symbol is km. Kilometre signs have stood beside roads since the French Revolution and spread with the metric system.
Compared with the mile
A kilometre is 0.6214 miles, or 62 per cent of a mile. Eight kilometres make almost exactly five miles, a handy ratio for runners.
Mile and kilometre compared
A mile is 60.9 per cent longer than a kilometre. A number of miles is therefore about five eighths of the same number of kilometres. A speed of 60 mph is 96.6 km/h; 100 km/h is 62 mph.
If you write for a mixed audience, give the unit of your main reader first and the other in brackets: 10 miles (16 km). In tables, use mi and km as symbols to avoid confusion with m for metre.
Where you will need it
Driving abroad
Speed limits in the United States are 25 mph in towns, 65 on highways and 75 on rural interstates: 40, 105 and 121 km/h. In the UK, 30, 60 and 70 mph are 48, 97 and 113 km/h. A driver used to kilometres must read the signs carefully and, if the speedometer has only mph, convert mi to km at least once to know what 60 means.
Fuel economy
Cars in the United States are rated in miles per gallon. A car doing 30 mpg uses 7.8 litres per 100 km. At 40 mpg it uses 5.9 litres. The conversion is not simply miles to kilometres but also gallons to litres, so the two factors are combined.
Running and walking
Races are often listed in miles: 5 mi is 8.05 km; 10 mi is 16.09 km; the mile itself is 1.609 km. A walker who reads that a trail is 6.4 mi long should know that this is 10.3 km, about two and a half hours at a normal pace.
Long trails
The Appalachian Trail is 2,190 mi, 3,525 km. The Pacific Crest Trail is 2,650 mi, 4,265 km. Walkers cover 15 to 20 miles a day, 24 to 32 km, and finish in five or six months.
Cities and roads in America
Typical distances
New York to Chicago is about 790 mi, 1,271 km. Los Angeles to San Francisco, 380 mi, 612 km. Chicago to Los Angeles, 2,015 mi, 3,243 km. Miami to Seattle, 3,300 mi, 5,311 km. These are the drives people dream of and plan.
Time and distance
At 65 mph, 105 km/h, the Los Angeles to San Francisco drive takes 5 hours 50 minutes. A day's drive of 500 mi, 805 km, takes about 8 hours.
Weather and storms
Reports in miles
American weather reports give visibility in miles and storm distance in miles. A thunderstorm 10 mi away is 16 km. Hurricane tracks show a radius of 100 mi, 161 km. Wind speeds are in mph: 74 mph, hurricane force, is 119 km/h.
Rainfall and snow
Rain is in inches, but the area of a storm is in miles. A line of storms 200 mi long is 322 km.
A short history
Mile and metric
The mile was fixed in 1593; the kilometre was created in the 1790s. The US adopted the metric system for science in 1866 and the Metre Convention in 1875. The mile stayed in everyday use. The 1959 agreement fixed the mile at 1.609344 km.
Attempts to change
The US Metric Conversion Act of 1975 encouraged metric use but made it voluntary. A few road signs in kilometres appeared in the 1970s, then were removed. The UK has never changed its signs.
Language and symbols
Symbols
Mile is mi and kilometre km. Do not write m for mile, because it means metre. Mph is miles per hour and km/h kilometres per hour. Put a space between number and unit.
Words
The word mile comes from the Latin mille, thousand. The kilometre, too, contains a thousand, in Greek. The two words share an ancestor in meaning though they differ in length.
A worked example: a road trip
Planning from a US guidebook
A guidebook describes a drive of 285 mi from Las Vegas to the Grand Canyon's north rim, with stops at 70 and 160 mi. To convert mi to km, multiply by 1.609344: the trip is 458.7 km, the stops 112.7 and 257.5 km. With a speed limit of 65 mph, 104.6 km/h, the drive takes 4.4 hours plus stops. Add fuel: at 25 mpg, 9.4 litres per 100 km, the car uses 43 litres.
Checking the numbers
Divide 458.7 by 1.609344 and you should return to 285. Check the fuel: 458.7 km times 9.4 per 100 is 43.1 litres. All figures agree.
Final checks
Three questions
After the conversion, ask whether the kilometre figure is bigger than the mile figure, whether the ratio is about 1.6 and whether it matches a rough estimate. If so, it is correct.
Round trip
Divide the kilometres by 1.609344. If you get your miles back, no digit has been lost.
Crossing a border by road
When the signs change
Drive from Canada into the United States and the signs switch from kilometres to miles at the border. A speed limit of 100 km/h becomes 65 mph, a distance of 250 km to the next city becomes 155 mi. Travellers who use both countries often keep a small card in the glove box: 30 mph is 48 km/h, 45 mph is 72, 55 is 88, 65 is 105, 75 is 121. The card saves a “convert mi to km” calculation on the spot.
Fuel and tolls
Fuel is sold in gallons in the US, 3.785 litres, and in litres in Canada. A tank of 15 gallons is 56.8 litres. Together with miles per gallon, the conversions chain: 30 mpg at 100 mi means 3.33 gallons, 12.6 litres, for 161 km.
Walking tours and city breaks
Distances that guides give
City guides in the United States and Britain describe walks in miles: "a 2 mile loop", "a 5 mile ramble". For a visitor, 2 mi is 3.2 km, about 40 minutes at a leisurely pace, and 5 mi is 8 km, an easy half day. Tourist maps show a scale bar in miles in the corner, with a smaller one in kilometres.
Planning your day
Add up the distances in miles, then convert mi to km once for the total: a day with three walks of 1.5, 2 and 3 mi covers 6.5 mi, 10.5 km. That is a comfortable day if you have time for rests and lunch.
Britain's road signs
Miles in a metric country
The UK is officially metric but uses miles on road signs. A town 20 miles away is 32 km. A motorway junction in 3/4 mile is 1.2 km. British drivers think in miles per hour and miles per gallon, while the rest of Europe uses kilometres and litres per 100 km.
Visiting from the continent
A driver from France, Germany or Romania must remember that the signs say miles. At 30 mph in a village, the speed is 48 km/h. A speedometer with a small km/h scale helps.
The marathon and its relatives
Why 26.2
The marathon distance was fixed at 26 mi 385 yd at the 1908 London Olympics, to start at Windsor Castle and end in front of the royal box. That is 42,195 m, 42.195 km. The odd distance became standard in 1921.
Other race lengths
The half marathon is 13.1 mi, 21.1 km. A 10K is 6.2 mi. A 5K is 3.1 mi. An ultra of 50 mi is 80.5 km; of 100 mi, 160.9 km.
Fuel and cost
Cost per mile
American drivers think in cost per mile: 0.60 dollars per mile is a typical full cost. In kilometres that is 0.37 dollars per km. A trip of 100 mi costs 60 dollars, a trip of 160.9 km costs the same.
Rental cars
Rental firms may include 100 miles per day free, 161 km, and charge extra beyond. For a trip of 250 km a day, check whether the limit is in miles or kilometres.
The Fibonacci conversion
How to use it
Find the number in the Fibonacci sequence closest to the miles and take its successor as kilometres: 13 mi is 21 km, 21 mi is 34 km, 34 mi is 55 km, 55 mi is 89 km. For other numbers, split into Fibonacci pieces: 40 is 34 plus 5 plus 1; so 55 plus 8 plus 2 is 65, against 64.4.
Limits
The trick is accurate to under 1 per cent for small numbers but fails when the pieces multiply the error. For precise work use 1.609344.
Odometers and used cars
Reading miles on the dash
A used car imported from the US or UK may show its mileage in miles. An odometer reading of 60,000 mi is 96,560 km. A service interval of 5,000 mi is 8,047 km. Buyers should check whether a car has been converted or not.
Estimating wear
An average car does 12,000 mi a year in the US, 19,300 km. A car with 120,000 mi, 193,000 km, is ten years old in American terms. Keep both figures in mind when you compare.
Spreadsheet formulas
Formula
To convert mi to km for a column, put miles in column A and enter =A2*1.609344 in column B. Format with one or two decimals. To go the other way, divide by 1.609344. For speeds, the same formula turns mph into km/h.
Check values
Enter 1: 1.609344. Enter 100: 160.9344. If you get 62.1, you are going the wrong way.
Rounding
Match the source
A road sign showing 12 miles is accurate to about half a mile, so 19 km is enough. Writing 19.31 km suggests more precision than the sign has. When the miles are exact, as in a marathon, keep all digits.
Safety
When planning fuel or timing, round the kilometre figure up. A trip of 76 mi is 122.3 km: plan for 125.
Teaching the conversion
Two scales on a map
To teach the “convert mi to km” calculation, give students a map with a scale in both miles and kilometres. They measure a route in miles and read the same distance in kilometres, discovering that the ratio is always 1.6. Repeat with three routes of different lengths.
Game
One student calls a speed in mph and the other gives km/h. Using the Fibonacci trick, they can answer within a second.
More values for convert mi to km
A longer list of conversions
If the value you need is not in the first list, these further conversions may be close enough to read off directly:
- 0.1 mi = 0.1609344 km
- 0.5 mi = 0.804672 km
- 3 mi = 4.828032 km
- 4 mi = 6.437376 km
- 7 mi = 11.265408 km
- 15 mi = 24.14016 km
- 20 mi = 32.18688 km
- 75 mi = 120.7008 km
- 200 mi = 321.8688 km
- 500 mi = 804.672 km
- 2,000 mi = 3,218.688 km
- 10,000 mi = 16,093.44 km
Mistakes when you convert mi to km
Dividing instead of multiplying
The mile is longer, so the number of kilometres is larger. If 10 mi becomes 6.2, you divided.
Using 1.5
1.5 is an under-estimate of 7 per cent. Use 1.6 for estimates and 1.609344 for precision.
Mixing nautical miles
A nautical mile is 1.852 km. A road sign always means the statute mile.
Quick answers
How many kilometres in a mile?
1.609344.
How do I convert mi to km?
Multiply by 1.609344.
What is 60 mph in km/h?
96.56 km/h.
Is the conversion exact?
Yes, the mile is defined as exactly 1,609.344 m.
Does my number leave my device?
No. The calculation runs in your browser.
Related pages and a last word
If you work with lengths, these conversions are close at hand: Convert mi to yd, Convert mi to ft, Convert nmi to km, Convert ly to km, Convert km to ly, Convert °C to °F, Convert °F to °C, Convert L to gal, Convert gal to L. The reverse of this page is Convert km to mi.
In short, to convert mi to km multiply by 1.609344, check with the multiply-by-8-divide-by-5 rule and keep only the digits your measurement supports. Your number stays on your device: nothing is uploaded and no account is needed.