Speed Converter

Use this free online converter to easily convert between units for measuring speed (magnitude of velocity). Metric and imperial units for measuring speed are supported.

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What units of speed are supported?

Speed is the distance covered in a specified slice of time. Naturally, speed is measured in units of distance divided by units of time. This versatile speed converter supports conversions between imperial units, between metric units, as well as converts from metric to imperial, and vice versa. You can convert units used for measuring speed such as meters per second, kilometers per hour, miles per hour, feet per second, yards per second, and knots (nautical miles per hour, Mph).

This online velocity converter uses definitions for the units of speed as they are established by international treaty in 1959 and as defined by the International System of Units (SI) [1] whose definitions are followed universally around the world. It is also in accord with the ISO standards for quantities and units [2]. The symbol convention is the one defined by SI. In some locations the standards may not be followed on a regular basis, e.g. the same symbol: "m", may be used for both miles and meters, causing potential confusion like between "mph" being used both for miles per hour and for meters per hour. Given the relative rarity of the latter unit, it is usually safe to assume "mph" stands for miles per hour.

The conversion output is accurate to ten decimal places: more than enough for most applications where a length converter is needed.

Some of you might be wondering about the difference between velocity and speed. Velocity is basically a directed movement with a certain speed, while speed, being a description of the magnitude of the velocity, has no direction (it is a scalar quantity).

Speed conversion. Imperial vs. Metric units.

Since 1959 both metric and imperial units of speed are defined using the standard meter (metre in British English) as a base unit. Consequently, all metric units for measuring velocity are expressed relative to it, e.g. a kilometer is 1,000 meters. To convert between metric units one needs to take into account the length dimension and the time dimension. E.g. in converting meters per second to km per hour, you need to multiply by 3600 to account for the 3600 seconds in an hour, and also divide by 1,000 to account for the length dimension, resulting in a multiplication by 3.6 (see more examples below).

Imperial units can trace their lineage further back in history but are currently in official use only in the United States, United Kingdom, and a couple of other countries in the world like Australia, while the metric system is official in the rest of the world. The same logic of conversion applies to conversions from one imperial unit to another, with both dimensions taken into account.

When converting from metric to imperial or from imperial to metric units of speed, the logic is the same, only the multiplication or division factor is different. Since all imperial units are defined in terms of the meter, the conversions are exact and not approximate, as can be the case with a few fringe measurement units in other areas.

speed velocity

Speed conversion examples

There are many possible conversions between the metrics supported in our length converter above. Some selected examples are below.

KiloMeters per hour to Miles per hour conversion example

Sample task: convert 50 km/h to mph. Solution:

Formula:
km/h / 1.609344 = mph
Calculation:
50 km/h / 1.6093 = 31.068560 mph
End result:
50 km/h is equal to 31.068560 mph


Miles per hour to KiloMeters per hour conversion example

Sample task: convert 30 mph to km/h. Solution:

Formula:
mph * 1.609344 = km/h
Calculation:
30 mph * 1.6093 = 48.280320 km/h
End result:
30 mph is equal to 48.280320 km/h


Km per hour to Meters per second conversion example

Sample task: convert 5 km/h to m/s. Solution:

Formula:
km/h / 3.6 = m/s
Calculation:
100 km/h / 3.60 = 27.777778 m/s
End result:
100 km/h is equal to 27.777778 m/s


Miles per hour to Foot per second conversion example

Sample task: convert 60 mph to ft/s. Solution:

Formula:
mph * 1.466666 = ft/s
Calculation:
60 mph * 1.4667 = 87.999960 ft/s
End result:
60 mph is equal to 87.999960 ft/s


Speed conversion tables

Below are conversion tables for a few of the most used pairs of units for measuring speed. You can use these for quick reference or use our velocity converter above for any other value or pair of interest. Our tool also works offline: you can use it as long as the page is cached in your browser.

Kilometers per hour to miles per hour conversion table:

km/h to mph conversion table
km/h mph
1 km/h 0.621371 mph
2 km/h 1.242742 mph
3 km/h 1.864114 mph
4 km/h 2.485485 mph
5 km/h 3.106856 mph
6 km/h 3.728227 mph
7 km/h 4.349598 mph
8 km/h 4.970970 mph
9 km/h 5.592341 mph
10 km/h 6.213712 mph
20 km/h 12.427424 mph
30 km/h 18.641136 mph
40 km/h 24.854848 mph
50 km/h 31.068560 mph
60 km/h 37.282272 mph
70 km/h 43.495983 mph
80 km/h 49.709695 mph
90 km/h 55.923407 mph
100 km/h 62.137119 mph

Miles per hour to kilometers per hour conversion table:

mph to km/h conversion table
mph km/h
1 mph 1.609344 km/h
2 mph 3.218688 km/h
3 mph 4.828032 km/h
4 mph 6.437376 km/h
5 mph 8.046720 km/h
6 mph 9.656064 km/h
7 mph 11.265408 km/h
8 mph 12.874752 km/h
9 mph 14.484096 km/h
10 mph 16.093440 km/h
20 mph 32.186880 km/h
30 mph 48.280320 km/h
40 mph 64.373760 km/h
50 mph 80.467200 km/h
60 mph 96.560640 km/h
70 mph 112.654080 km/h
80 mph 128.747520 km/h
90 mph 144.840960 km/h
100 mph 160.934400 km/h

Meters per second to kilometers per hour conversion table:

m/s to km/h conversion table
m/s km/h
1 m/s 3.60 km/h
2 m/s 7.20 km/h
3 m/s 10.80 km/h
4 m/s 14.40 km/h
5 m/s 18 km/h
6 m/s 21.60 km/h
7 m/s 25.20 km/h
8 m/s 28.80 km/h
9 m/s 32.40 km/h
10 m/s 36 km/h
20 m/s 72 km/h
30 m/s 108 km/h
40 m/s 144 km/h
50 m/s 180 km/h
60 m/s 216 km/h
70 m/s 252 km/h
80 m/s 288 km/h
90 m/s 324 km/h
100 m/s 360 km/h

Feet per second to miles per hour conversion table:

ft/s to mph conversion table
ft/s mph
1 ft/s 0.681818 mph
2 ft/s 1.363637 mph
3 ft/s 2.045455 mph
4 ft/s 2.727274 mph
5 ft/s 3.409092 mph
6 ft/s 4.090911 mph
7 ft/s 4.772729 mph
8 ft/s 5.454548 mph
9 ft/s 6.136366 mph
10 ft/s 6.818185 mph
20 ft/s 13.636370 mph
30 ft/s 20.454555 mph
40 ft/s 27.272740 mph
50 ft/s 34.090925 mph
60 ft/s 40.909110 mph
70 ft/s 47.727294 mph
80 ft/s 54.545479 mph
90 ft/s 61.363664 mph
100 ft/s 68.181849 mph

References:

[1] NIST Special Publication 330 (2008) - "The International System of Units (SI)", edited by Barry N.Taylor and Ambler Thompson

[2] International Organization for Standardization (1993). ISO Standards Handbook: Quantities and units (3rd edition). Geneva: ISO. ISBN 92-67-10185-4.

Cite this converter & page

If you'd like to cite this online converter resource and information as provided on the page, you can use the following citation:
Georgiev G.Z., "Speed Converter", [online] Available at: https://www.gigacalculator.com/converters/speed-converter.php URL [Accessed Date: 18 Jun, 2019].