Convert mph to km/h

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Type a speed in miles per hour and the result in kilometers per hour appears as you type. At 70 mph the converter shows 112.6541 km/h, which is the UK motorway limit in the unit used on metric road signs.

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What is a mile per hour and how does it relate to km/h?

A mile per hour (mph) is a unit of speed in the British imperial system and in the United States customary system. It gives the number of miles traveled in one hour[1].


The mile in that name is the statute mile. It is 1,760 yards long and has measured exactly 1.609344 kilometers since 1 July 1959[2].


So one mile per hour is exactly 1.609344 km/h. In meters per second that is 0.44704 m/s[1].


Railways in the United States, Canada and Ireland give speeds in miles per hour[1]. In some countries the speed of the ball in cricket, tennis and baseball is given in mph as well[1].

Two round speed limit signs showing 30 beside a narrow lane, with an Oldstead name sign
These speed limit signs stand at the entrance to the village of Oldstead in North Yorkshire, England. They show only the number 30, which means 30 mph, or 48.28 km/h. Photo: Kwami Fattah Al Sissi, Unsplash.

How many km/h is 70 mph?

70 mph is 112.65 km/h. To convert mph to km/h, multiply the speed in miles per hour by 1.609344.


The same multiplication translates the limits on British road signs, which show speed in miles per hour[3]. In built-up areas of England, Scotland and Northern Ireland the limit is 30 mph. Converted, that is 48.28 km/h. On a single carriageway outside built-up areas you may drive at up to 60 mph. That gives 96.56 km/h. The 70 mph limit applies on dual carriageways and motorways.


In Wales the default limit in built-up areas is 20 mph. In kilometers per hour that is 32.19 km/h.


The sum helps when you explain a British or American limit to a visitor from a country where signs show km/h.


Formula: km/h = mph × 1.609344


The multiplier 1.609344 is exact, because it follows directly from the length of the mile. The result field shows four decimal places, while the tables round to hundredths.

How to convert 65 mph to km/h: formula and example

The conversion is a single multiplication: km/h = mph × 1.609344.


Take 65 mph, a limit found on highways along the Eastern Seaboard of the United States[4]. Multiplying it by 1.609344 gives 104.61 km/h.


A quick estimate comes from multiplying by 1.6. For 65 mph that gives 104 km/h, which is 0.61 km/h below the exact result.


The shortcut comes out about 0.6% low, because a mile is slightly longer than 1.6 kilometers. At the speeds on road signs the gap stays under one kilometer per hour.


The km/h to mph converter handles the reverse conversion. A distance from an American map converts with the miles to km converter.

White SPEED LIMIT 55 sign on a wooden post beside a road with dry grass and hills
This sign limits speed on a road in the United States to 55 mph. Converted, that is 88.51 km/h. Photo: Ludovic Charlet, Unsplash.

How many km/h is a given speed in mph?

Speeds from 1 to 500 mph, with the result in kilometers per hour and in meters per second.
Miles per hourKilometers per hour (km/h)Meters per second (m/s)
1 mph1.61 km/h0.45 m/s
2 mph3.22 km/h0.89 m/s
3 mph4.83 km/h1.34 m/s
5 mph8.05 km/h2.24 m/s
10 mph16.09 km/h4.47 m/s
15 mph24.14 km/h6.71 m/s
20 mph32.19 km/h8.94 m/s
25 mph40.23 km/h11.18 m/s
30 mph48.28 km/h13.41 m/s
35 mph56.33 km/h15.65 m/s
40 mph64.37 km/h17.88 m/s
45 mph72.42 km/h20.12 m/s
50 mph80.47 km/h22.35 m/s
55 mph88.51 km/h24.59 m/s
60 mph96.56 km/h26.82 m/s
65 mph104.61 km/h29.06 m/s
70 mph112.65 km/h31.29 m/s
75 mph120.7 km/h33.53 m/s
80 mph128.75 km/h35.76 m/s
85 mph136.79 km/h38 m/s
90 mph144.84 km/h40.23 m/s
95 mph152.89 km/h42.47 m/s
100 mph160.93 km/h44.7 m/s
110 mph177.03 km/h49.17 m/s
120 mph193.12 km/h53.64 m/s
125 mph201.17 km/h55.88 m/s
130 mph209.21 km/h58.12 m/s
140 mph225.31 km/h62.59 m/s
150 mph241.4 km/h67.06 m/s
155 mph249.45 km/h69.29 m/s
160 mph257.5 km/h71.53 m/s
170 mph273.59 km/h76 m/s
180 mph289.68 km/h80.47 m/s
190 mph305.78 km/h84.94 m/s
200 mph321.87 km/h89.41 m/s
220 mph354.06 km/h98.35 m/s
230 mph370.15 km/h102.82 m/s
240 mph386.24 km/h107.29 m/s
250 mph402.34 km/h111.76 m/s
300 mph482.8 km/h134.11 m/s
400 mph643.74 km/h178.82 m/s
500 mph804.67 km/h223.52 m/s
The rows for 20, 30, 60 and 70 mph match the limits on British road signs[3]. The meters per second column gives the same speed in the SI unit.

What are UK and US speed limits in km/h?

Speed limits from British and American rules, converted to kilometers per hour.
Where it appliesLimit in mphLimit in km/h
Wales: default limit in built-up areas since 17 September 202320 mph32.19 km/h
England, Scotland and Northern Ireland: built-up areas30 mph48.28 km/h
United Kingdom: single carriageway outside built-up areas60 mph96.56 km/h
United Kingdom: dual carriageway and motorway70 mph112.65 km/h
United States: upper limit tied to federal highway funds, 1974 to 198755 mph88.51 km/h
United States: Texas State Highway 130, the highest limit in the country85 mph136.79 km/h
The UK values apply to cars, and the 70 mph limit was introduced as a temporary measure on 22 December 1965[3]. From 1974 to 1987 federal law withheld highway funds from states with limits above 55 mph[4]. Quebec limits converted to mph are on the page of the km/h to mph converter.

How many km/h is the wind in each hurricane category?

The Saffir-Simpson scale from the official National Hurricane Center page, with wind speed in mph and in km/h.
Hurricane categoryWind in mphWind in km/h
Category 174–95 mph119–153 km/h
Category 296–110 mph154–177 km/h
Category 3111–129 mph178–208 km/h
Category 4130–156 mph209–251 km/h
Category 5157 mph or higher252 km/h or higher
The ranges come from the National Hurricane Center[5]. The km/h limits there are rounded to whole numbers. Converting a limit in the converter therefore gives a result with decimals, for example 95 mph comes to 152.89 km/h.

Which number formats does this converter accept?

The field reads every one of these formats and converts it, so there is nothing to tidy up before you paste. The table shows what the converter does with each entry, and the converter worked out every result itself.
What you typeWhat the converter showsHow we read it
70112.6541 km/hA number on its own is read as miles per hour, because that is the unit on the field.
70mph112.6541 km/hThe mph symbol pasted with the number, with or without a space and in capitals as on US signs, is skipped.
62.5100.584 km/hThe decimal point separates the fraction, exactly as you would expect.
62,5100.584 km/hA comma followed by one or two digits can only be a decimal comma, so the result is the same.
1,5002,414.016 km/hA comma before three digits groups thousands in English, so this is fifteen hundred miles per hour. A note under the field shows the other possible reading, 1.5.
1.5002.414 km/hA single point is always read as a decimal point, so the field counts one and a half miles per hour. A note under the field shows the other possible reading, 1500.
1 5002,414.016 km/hA space between the thousands, as written in much of Europe and in SI style, gives the same result as 1,500.
100 km/h100 km/hKilometres per hour are converted to miles per hour, with a line under the field saying so, so the result comes back to 100 km/h.

How do you convert a limit from a US or UK road sign to km/h?

Four steps let you compare a limit posted in miles per hour with a speed in kilometers per hour.

  1. Type the number from the sign

    In the Miles per hour field, type the limit from the sign, for example 55.

  2. Read the result in km/h

    The converter shows 88.5139 km/h. That is the value to find on a scale in kilometers per hour.

  3. Save the result

    The Copy result button puts the number on your clipboard, for example for a note with your route plan.

  4. Clear the fields before the next limit

    The Clear all button empties both fields, so you type the next value from a sign from the start.

Sources

  1. Miles per hour — Wikipedia
  2. Mile — Wikipedia
  3. Speed limits in the United Kingdom — Wikipedia
  4. Speed limits in the United States — Wikipedia
  5. Saffir-Simpson Hurricane Wind Scale — National Hurricane Center (NOAA)
  6. Speed limits in Ireland — Wikipedia
  7. Puerto Rican units of measurement — Wikipedia

Every figure in the tables was computed from the unit definitions and checked arithmetically before publication. Historical values and the names of local units come from the sources listed above.

Content last reviewed: · written and checked by the Arteon team

Common questions about converting mph to km/h

Which is faster, 1 mph or 1 km/h?

A mile per hour is faster, because a mile is longer than a kilometer. With the same number on the sign, a speed in mph is about 61% higher than a speed in km/h.

Why are speed limits in km/h in Ireland but in mph in Northern Ireland?

Ireland adopted metric speed limits on 20 January 2005[6]. Around 35,000 existing signs were replaced. A further 23,000 new signs went up, and each one carries km/h beneath the numerals[6]. Northern Ireland is part of the United Kingdom, where signs show limits in miles per hour[3].

Where else besides the US and the UK are speeds given in mph?

Several smaller countries and territories use miles per hour, among them Liberia, the Bahamas, Belize and Grenada[1]. Puerto Rico mixes the two: distance signs are in kilometers, while speed limits are in miles per hour[7].

Is a mile per hour the same in the UK and the US?

Yes. The 1959 international yard and pound agreement gave the United States, the United Kingdom, Canada, Australia, New Zealand and South Africa the same mile[2]. The converter result is therefore correct for a speed from either country.

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