Online Speed Converter

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Speed Converter


Please enter a number:
Mile/hour (mph)
Kilometer/hour​ (kmh)
Foot/second (fts)
Meter/second (ms)
Knot‌ (knot)

This speed converter can convert between different speed units, you just need to enter a original value and select the original unit in combobox, converter will quickly calculate all the values of other speed units.

How to Convert Units of Speed

Conversions are performed by using a conversion factor. By knowing the conversion factor, converting between units can become a simple multiplication problem:

S * C = E

Where S is our starting value, C is our conversion factor, and E is our end converted result.

To simply convert from any unit into meters per second, for example, from 5 mph, just multiply by the conversion value in the right column in the table below.

5 mph * 0.44704 [ (m/s) / (mph) ] = 2.2352 m/s

To convert from m/s into units in the left column divide by the value in the right column or, multiply by the reciprocal, 1/x.

2.2352 (m/s) / 0.44704 [ (m/s) / (mph) ] = 5 mph

To convert among any units in the left column, say from A to B, you can multiply by the factor for A to convert A into meters per second then divide by the factor for B to convert out of meters per second. Or, you can find the single factor you need by dividing the A factor by the B factor.

For example, to convert from miles per hour to kilometers per hour you would multiply by 0.44704 then divide by 0.2777778. Or, multiply by 0.44704/0.27777778 = 1.6093439. So, to convert directly from mph to km/h (kph), you multiply by 1.6093439.

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 speed 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). The same logic of conversion applies to conversions from one imperial unit to another, with both dimensions taken into account.

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, while the metric system is official in the rest of the world. Using a speed converter can be considered one way to bring these countries closer together, as it doesn't seem either side is willing to forgo its speed unit system.

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.