Meters per Second to Miles per Hour
1 m/s = 2.2369363 mph. Type in either box.
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Metres per second into miles per hour
Multiply by 2.2369363. Doubling and adding ten per cent is a good mental approximation.
1 m/s = 2.2369363 mph
The conversion turns up whenever a measurement made in SI units has to be reported to a British or American audience — wind speed, ball speed, vehicle testing.
Metres per second
The SI unit of speed, and the one physics uses because it drops straight into equations without conversion. Walking pace is about 1.4 m/s; a sprinter peaks near 12 m/s; sound travels at roughly 343 m/s in air at room temperature.
It is rarely used for vehicles, because the numbers are small and unintuitive — a motorway speed of 30 m/s does not feel like anything to most people. It is standard for wind speed in meteorology and for anything going into a calculation.
Miles per hour
The road speed unit in the United States and the United Kingdom, and still common in aviation for ground speed. One mile per hour is exactly 0.44704 m/s, because the mile is defined exactly in metres.
Against kilometres per hour the factor is 1.609344 — the same number as miles to kilometres, since the hour cancels on both sides.
The working, step by step
Every line updates with whatever you type above. The point is the method, which is the same for any pair of units in this family.
The same quantity, two different numbers
One physical amount, read off two scales. The tick marks do not line up, and the gap between them is the conversion factor made visible.
How much is that?
A number is easier to judge next to something familiar.
Your turn
Reading a method and being able to use it are different things. Answer within half a per cent and it counts as correct.
Score: 0 of 0
How to use this converter
- Type into either box. The other side updates as you go; there is no button to press.
- Swap the direction with the button between the boxes, carrying your value across.
- Set the decimals if the default is more or less precision than you need.
- Copy the answer with its unit, ready to paste.
- Use the shortcut buttons for the values that come up most often.
- Share the result. The address bar tracks what you type, so the link you copy opens on the same number.
Common uses and tips
Where speed conversions come up
- Driving abroad. A 100 km/h limit is 62 mph; a 70 mph limit is 113 km/h. Hire cars usually show both, but the signs show only one.
- Weather. Wind speed comes in km/h, mph, knots or metres per second depending on the service. Storm warnings are almost always in knots at sea and mph or km/h on land.
- Running and cycling. Apps report pace in minutes per kilometre or per mile and speed in km/h or mph, often on the same screen.
- Physics and engineering. Anything going into a formula needs metres per second, because that is what the SI equations expect.
- Aviation and sailing, where knots are standard because a nautical mile is one minute of latitude.
Numbers worth carrying
- km/h to m/s: divide by 3.6. Exactly, with no rounding — 3,600 seconds in an hour, 1,000 metres in a kilometre.
- mph to km/h: multiply by 1.609344. Adding 60 % is a good mental version: 70 mph + 60 % = 112, against a true 112.7.
- knots to mph: add about 15 %. One knot is 1.15078 mph.
- The speed of sound is about 343 m/s, or 1,235 km/h, or 767 mph at room temperature. It falls as the air gets colder, which is why an aircraft's Mach number changes with altitude at constant airspeed.
Mistakes worth avoiding
- Speed and pace are reciprocals. Doubling your speed halves your pace. Converting one as though it were the other gets the arithmetic backwards.
- A knot is already "per hour". There is no such thing as "knots per hour" for speed — the hour is inside the unit.
- Rounding matters at speed limits. 30 mph is 48.3 km/h, and a limit posted as 50 km/h is 31 mph, which is not the same thing.
Values people look up most
Each one opens the converter with the number already in it.
- 1 m/s to mph
- 2 m/s to mph
- 5 m/s to mph
- 10 m/s to mph
- 15 m/s to mph
- 20 m/s to mph
- 25 m/s to mph
- 30 m/s to mph
- 50 m/s to mph
- 100 m/s to mph
Quick reference
| Metres per second | Miles per hour |
|---|---|
| 1 m/s | 2.236936 mph |
| 5 m/s | 11.184681 mph |
| 10 m/s | 22.369363 mph |
| 20 m/s | 44.738726 mph |
| 30 m/s | 67.108089 mph |
| 50 m/s | 111.846815 mph |
| 100 m/s | 223.693629 mph |
| 343 m/s | 767.269148 mph |
Questions people ask
What is the formula?
Multiply metres per second by 2.2369363.
What is 20 m/s in mph?
44.74 mph.