How fast is 40 km an hour

Definition: The unit kilometers per hour (symbol: km/h) is a unit of speed expressing the number of kilometers traveled in one hour.

History/origin: The unit of kilometers per hour is based on the meter, which was formally defined in 1799. According to the Oxford English Dictionary, the term kilometer first came into use in 1810. It was not until later in the mid-late 19th century however, that the use of kilometers per hour became more widespread; the myriametre (10,000 meters) per hour was preferred for expressing speed.

Current use: Km/h is currently the most commonly used unit of speed around the world and is typically used for car speeds and road signs. It is also common for both miles per hour as well as kilometers per hour to be displayed on car speedometers. There are many abbreviations for the unit kilometers per hour (kph, kmph, k.p.h, KMph., etc.), but "km/h" is the SI unit symbol.

Mile/hour

Definition: The unit miles per hour (symbol: mph) is a measurement of speed in the imperial and United States customary systems. It expresses the number of statute miles traveled over the period of one hour. One mph equals exactly 1.609344 kilometers per hour (km/h).

Current use: Along with km/h, mph is most typically used in relation to road traffic speeds. It is most widely used in the United States, the United Kingdom, and their related territories. It is also used in the Canadian rail system, though the Canadian road systems use km/h.

This is a measurement of speed typically used in non-metric countries for transport such as the USA. The United Kingdom also uses this on the roads although officially the metric system has been adopted. Road speed limits are given in miles per hour which is abbreviated as mph or mi/h.

Change the units for other conversions like km to mph, mph to km, etc. The results calculate automatically.

How many miles per hour are in 40 kilometers per hour? What is 40 kilometers per hour in miles per hour? How fast is 40 kilometers per hour in other units of measure? How slow? Type into the calculator inputs to calculate a different speed. Browse below to see calculations for other numbers.

Here we will explain and show you how to convert 40 kilometers per hour to miles per hour. Kilometers per hour can be abbreviated to km/h or kmh and miles per hour can be shortened to mph.

To calculate how fast 40 kmh is in mph, you need to know the kmh to mph formula. There are 0.621371192 miles per kilometer. Therefore, the formula and the math to convert 40 kmh to mph is as follows:

kmh × 0.621371192 = mph
40 × 0.621371192 = 24.85484768
40 kmh ≈ 24.85 mph


Below is an image of a speedometer showing the needle pointing at 40 kmh. The speedometer shows the kmh in black and mph in orange so you can see how the two speeds correspond visually.

kmh to mph Converter
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40.1 kmh to mph
Here is the next speed in kilometers per hour (kmh) that we have converted to miles per hour (mph) for you.

The inverse of the conversion factor is that 1 mile per hour is equal to 0.0402336 times 40 kilometers per hour.

It can also be expressed as: 40 kilometers per hour is equal to 10.0402336 miles per hour.

Units involved

This is how the units in this conversion are defined: