Converters

Speed Converter

Convert speed between kilometers per hour, miles per hour, meters per second, feet per second and knots, with a full conversion table.

Converters · Speed ConverterRuns in your browser

From

0.621371

1 km/h = 0.621371 mph

Unit	1 km/h =
Meters per second	0.277778 m/s
Kilometers per hour	1 km/h
Miles per hour	0.621371 mph
Feet per second	0.911344 ft/s
Knots	0.539957 kn

How to convert a speed

Put the speed figure in the From field — it starts at 1 with kilometers per hour selected.
If your number is in m/s, mph, ft/s or knots, choose that unit from the dropdown beneath it.
Miles per hour is the default output; pick another unit on the right if you need it.
Glance at the table under the result to see the same speed in all five units.
Press the swap arrows to turn km/h → mph into mph → km/h instantly.

Five speed units and their exact values in meters per second

Meters per second is the base unit. Two of the factors are stored as fractions rather than rounded decimals: a kilometer per hour is 1,000 ÷ 3,600 m/s and a knot is 1,852 ÷ 3,600 m/s, so the recurring digits are carried in full. Miles per hour is exact because a mile is exactly 1,609.344 m and an hour is 3,600 s.

Unit	Symbol	Meters per second	Where it is used
Meters per second	m/s	1	Physics, engineering, wind reports in some countries
Kilometers per hour	km/h	0.277778 (1,000 ÷ 3,600)	Road signs in most of the world
Miles per hour	mph	0.44704	Road signs in the US and UK
Feet per second	ft/s	0.3048	US engineering, ballistics, sport
Knots	kn	0.514444 (1,852 ÷ 3,600)	Aviation, shipping, marine weather

Speed units in the converter.

Working through a conversion

To turn 30 knots into km/h, the widget first finds the base value: 30 × 0.514444 = 15.4333 m/s. It then divides by the km/h factor: 15.4333 ÷ 0.277778 = 55.56 km/h, exactly what you get from the shortcut 30 × 1.852. The same input in mph is 15.4333 ÷ 0.44704 = 34.5234 mph.

60 mph in feet per second is a classic: 60 × 0.44704 = 26.8224 m/s, and 26.8224 ÷ 0.3048 = 88 ft/s. Floating-point arithmetic actually returns 87.99999999999999, and the display rounding turns that back into 88.

How the figures are rounded

At 100 or above the widget keeps two decimals, so 100 m/s shows as 360 km/h with the zeros trimmed.
Between 1 and 100 it keeps four decimals: 12 km/h is 3.3333 m/s.
Under 1 it keeps six decimals, which is why 1 km/h appears as 0.277778 m/s.
Grouping and decimal symbols come from your browser locale rather than being fixed.

One unit expressed in the other four

Enter 1 in any unit and the table under the result is effectively this grid. It is a quick way to check an answer from memory: a meter per second is a little more than two miles per hour, and a knot sits between a mile per hour and a meter per second.

1 unit	m/s	km/h	mph	ft/s	kn
1 m/s	1	3.6	2.2369	3.2808	1.9438
1 km/h	0.277778	1	0.621371	0.911344	0.539957
1 mph	0.44704	1.6093	1	1.4667	0.868976
1 ft/s	0.3048	1.0973	0.681818	1	0.592484
1 kn	0.514444	1.852	1.1508	1.6878	1

Each row is one unit; columns show its value in the others, rounded as the widget prints them.

Why knots are still used at sea and in the air

A knot is one nautical mile per hour, and a nautical mile (1,852 m) is close to one minute of latitude. That makes distance, speed and time on a chart line up with the latitude scale, so navigators never need a separate conversion. Aircraft airspeed, ship speed, ocean currents and marine wind forecasts all use knots; 1 knot is 1.852 km/h or about 1.1508 mph.

Things this converter leaves out

Pace (minutes per kilometer or per mile) is not a unit here. Divide 60 by a km/h figure to get min/km: 12 km/h is 5:00 min/km.
Mach numbers, the speed of light and centimeters per second are not offered.
The tool converts speed only; it does not calculate travel time or distance from a speed.
Negative speeds are accepted and converted, treating the sign as direction.

Frequently asked questions

How do I convert km/h to mph?

Multiply the km/h value by 0.621371 to get mph. For example, 100 km/h × 0.621371 ≈ 62.14 mph.

What is a knot in mph?

One knot is one nautical mile per hour, which equals about 1.151 mph or 1.852 km/h.

How do I convert a speed to meters per second by hand?

Divide km/h by 3.6 (90 km/h = 25 m/s), or multiply mph by 0.44704 (60 mph = 26.82 m/s). The converter uses exactly these factors.

Why is 60 mph exactly 88 feet per second?

A mile is 5,280 ft and an hour is 3,600 s, so 1 mph is 5,280 ÷ 3,600 = 1.46667 ft/s. Multiplied by 60 that gives 88 ft/s, with no rounding involved.

Can the converter work out running pace per kilometer?

Not directly. Convert your speed to km/h, then divide 60 by it: 10 km/h gives 6:00 min/km, 12 km/h gives 5:00 min/km.

Does it convert Beaufort wind force?

No. Beaufort numbers are a scale of ranges, not a unit. Look up the knot range for the force (for example force 6 is 22–27 knots) and convert that with the tool.

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