100% free · Runs 100% in your browser · km/h, mph, m/s & knots · No signup needed
Type in any field and the rest update instantly. Displayed values are rounded to 2 decimal places, but the full-precision value is used for the next conversion — not the rounded display. 1 mph = 1.60934 km/h; 1 knot = 1.852 km/h; 100 km/h = 62.14 mph = 27.78 m/s.
Try an example: 60 mph = 96.56 km/h
| What | km/h | mph | m/s |
|---|---|---|---|
| Walking | 5 | 3.11 | 1.39 |
| Cycling | 20 | 12.43 | 5.56 |
| City driving | 50 | 31.07 | 13.89 |
| Motorway | 120 | 74.56 | 33.33 |
Speed is measured differently around the world. Roads in most countries use kilometres per hour, roads in the United States and the United Kingdom use miles per hour, scientists and engineers use metres per second, and sailors and pilots use knots. The Speed Converter translates between all four units instantly, so you can make sense of any speed figure you meet, wherever it comes from.
Type a speed into any of the four fields, kilometres per hour, miles per hour, metres per second or knots, and the other three update straight away. There is no need to remember conversion factors, no need to reach for a calculator, and no need to install anything, because the tool runs entirely in your browser and the conversion happens as you type.
Kilometres per hour, written km/h, is the standard road speed unit in most of the world. Miles per hour, written mph, is used on roads in the United States and the United Kingdom, and it is also common in older books and films. Metres per second, written m/s, is the unit scientists prefer, because it fits neatly with the metric system. Knots are used at sea and in the air, where one knot is one nautical mile per hour.
The factors between them are fixed. One mile per hour equals 1.60934 kilometres per hour, so to go from mph to km/h you multiply by 1.60934. One knot equals 1.852 kilometres per hour, a figure that comes from the definition of the nautical mile. And 100 km/h equals 62.14 mph and 27.78 m/s, which gives you a useful anchor point: a typical motorway speed in Europe is about 62 mph and about 28 metres every second.
Take 60 mph, a common speed limit in the United Kingdom. Multiply 60 by 1.60934 and you get 96.56 km/h, so 60 mph is roughly 97 km/h. Take 10 metres per second, a brisk running pace for a short sprint. Multiply by 3.6 and you get 36 km/h, and dividing that by 1.60934 gives about 22.37 mph. Both checks are built into the tool, so you can enter the numbers and see the same results for yourself.
Try a few more. A walking pace of 5 km/h is about 3.11 mph and about 1.39 m/s. A cycling speed of 20 km/h is about 12.43 mph and about 5.56 m/s. A motorway speed of 120 km/h is about 74.56 mph and about 33.33 m/s. After a few conversions, you will start to build a feel for the numbers, and the tool becomes a way to learn as well as a way to convert.
The tool includes a small table of common speeds to help you judge a number at a glance. Walking is about 5 km/h, cycling is about 20 km/h, city driving is often 50 km/h, motorway driving is often 120 km/h, and a fast train can travel at 300 km/h or more. Seeing these values side by side in different units makes it easier to understand a speed limit, a travel time, or a sports result from another country.
The table is also a good way to check your intuition. If a news story says a storm had winds of 100 km/h, the table tells you that is about 62 mph, which is a serious wind. If a runner is described as moving at 5 metres per second, the table tells you that is 18 km/h, which is fast for a human. Context turns a bare number into something meaningful.
The values on screen are rounded for readability, and the tool is honest about that. The full-precision value is used for the next conversion, not the rounded display, so converting back and forth does not accumulate rounding errors. If you see 62.14 mph for 100 km/h, the tool is keeping the full value behind the scenes, and a further conversion from that result will use the exact figure rather than the rounded one.
This matters when you chain conversions or copy a result into another calculation. A rounded number is fine for reading, but it is a poor starting point for more maths. By keeping the full value internally, the tool gives you clean displays without sacrificing accuracy in the background.
Travellers meet speed conversions constantly. A hire car dashboard may show km/h when you are used to mph, or a road sign may show a limit in a unit you do not normally use. Sports fans meet them when a race is reported in different units in different countries. Students meet them in physics, where speeds are often given in metres per second and need to be turned into km/h to compare with everyday speeds.
Drivers, cyclists and runners also use the converter to make sense of their own performance. A cyclist who averages 30 km/h wants to know what that is in mph. A runner who sees a pace in minutes per kilometre wants to know the equivalent speed. And anyone planning a journey wants to turn a speed and a distance into a realistic travel time, which you can do with the travel time calculator.
Speed limits are the most common place where unit confusion causes real problems. A driver used to miles per hour who hires a car in France or Germany will see limits in kilometres per hour, and a driver used to kilometres per hour who drives in the United States will see limits in miles per hour. Knowing that 50 km/h is about 31 mph, that 100 km/h is about 62 mph, and that 30 mph is about 48 km/h turns an unfamiliar sign into a number you can act on without guessing.
The same confusion appears in weather reports, where wind speeds may be given in kilometres per hour in one country and miles per hour in another, and in sports, where a cyclist in Europe measures speed in km/h while a runner in the United States thinks in minutes per mile. Converting quickly removes the guesswork, and after using the tool a few times you will start to remember the common equivalents without needing to look them up.
Scientists and engineers use metres per second because it fits the metric system and makes physics calculations simpler, but most people find km/h or mph easier to picture. A speed of 27.78 m/s sounds abstract, while 100 km/h is a familiar motorway speed. The converter bridges that gap, letting you move between the scientific unit and the everyday unit whenever you need to.
How fast is 100 km/h in mph? 100 km/h is 62.14 mph and 27.78 m/s. You can check it by typing 100 into the km/h field of the converter.
What is 60 mph in km/h? 60 mph is 96.56 km/h. Multiply miles per hour by 1.60934 to get kilometres per hour.
How many km/h is one knot? One knot is 1.852 km/h. Knots are used at sea and in the air, where speeds are measured in nautical miles per hour.
What is 10 m/s in km/h? 10 m/s is 36 km/h, which is about 22.37 mph. Multiply metres per second by 3.6 to get kilometres per hour.
Are the displayed values exact? The display is rounded for readability, but the tool uses the full-precision value for the next conversion, so accuracy is not lost when you convert again.
For more conversions, try the unit converter for lengths, weights and temperatures, and the running pace calculator if you want to turn a running time into a pace and a speed.
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Convert a speed, check it against the common values, and you will never be caught out by an unfamiliar unit again.
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