Convert m/s to mph metres per second ↔ miles per hour Free Online Secure
Type a value in metres per second and read it in miles per hour at once. The factor is exact by definition, the arithmetic happens in your browser, and nothing is sent anywhere.
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Convert to miles per hour
Common values — Convert m/s to mph (metres per second ↔ miles per hour)
| m/s | mph |
|---|---|
| 1 | 2.23693629205 |
| 2 | 4.47387258411 |
| 3 | 6.71080887616 |
| 5 | 11.1846814603 |
| 10 | 22.3693629205 |
| 20 | 44.7387258411 |
| 50 | 111.846814603 |
| 100 | 223.693629205 |
Where these units come from
Speed has no unit of its own: it is a length divided by a time, so every trade simply kept the length it was already using. That is why the same motion is 100 km/h on a European road sign, 62 mph on an American one and 27.8 m/s in a physics problem. The knot is the oldest of them and the most literal: sailors paid out a line with knots tied at even spacing and counted how many ran through their fingers while a sand glass emptied, so the speed was read off in knots. One knot is one nautical mile per hour, and a nautical mile is a minute of latitude — which is why ships and aircraft still use it. The speed of light is the odd one out: since 1983 it is not measured but fixed at exactly 299,792,458 m/s, because the metre is now defined from it.
Where you meet them
Kilometres and miles per hour live on speedometers and road signs, metres per second in physics, engineering and wind reports, feet per second in ballistics and in American machine shops. Knots carry shipping, aviation and marine weather, and Mach numbers appear wherever an aircraft is fast enough for the air's own stiffness to matter. The speed of light turns up less in daily life than in distances: a light year is simply how far it gets in one.
Questions people ask
Is Mach 1 a fixed speed?
No. Mach is a ratio to the speed of sound in the surrounding air, and sound travels more slowly in colder air. This page uses the standard sea-level figure, 340.294 m/s, so Mach 1 here is about 1225 km/h. At the altitude airliners cruise at, the air is some 50 degrees colder and the same Mach 1 is roughly a tenth slower. An aircraft can therefore hold a constant Mach number while its speed over the ground changes.
Why do ships and aircraft use knots rather than km/h?
Because a nautical mile is one minute of arc of latitude. A vessel making one knot covers one minute of latitude in an hour, so speed, time and position on a chart fit together without conversion. The same reasoning kept the nautical mile at exactly 1852 metres rather than rounding it to something tidier.
Is the answer exact?
Where both units are defined in terms of one another by whole numbers, yes — the page says so above the figure, and the only rounding is in how many digits are shown. Where the ratio has no finite decimal, the page shows twelve significant digits and says the relation is approximate rather than pretending otherwise.
Does anything I type leave my device?
No. The arithmetic runs in your browser; nothing is uploaded and there is no server to upload it to. Load the page once and it keeps working with the network switched off.
Nordic forecasts for American readers: from m/s to mph
Weather services in Norway, Sweden and Finland give wind in metres per second. A visitor from the United States planning a hike, a ferry or a flight reads "gusts to 18 m/s" and wonders whether to worry. The National Weather Service speaks in miles per hour, and its warning thresholds are fixed in those units. To convert m/s to mph, multiply by 2.2369: 5 m/s is 11.2 mph, 10 m/s is 22.4 mph and 18 m/s is 40.3 mph. The calculator above multiplies as you type, and the sections below show what the figures mean for wind warnings, storms and outdoor plans.
You will find the rule with worked examples, a short profile of each unit, a comparison, a long set of cases from weather and the slips to avoid. The arithmetic runs in your browser, and what you type is not sent anywhere. In severe weather, follow official warnings.
How to convert m/s to mph: multiply by 2.2369
The rule
One metre per second is 3.6 km/h, and one km/h is 0.6214 mph, so one m/s is 2.2369 mph. To convert m/s to mph, multiply the m/s figure by 2.2369. So 3 m/s is 6.7 mph, 12 m/s is 26.8 mph and 25 m/s is 55.9 mph. To go back, multiply by 0.447.
Worked examples
A light breeze of 2 m/s is 4.5 mph. A fresh wind of 8 m/s is 17.9 mph. A gale of 20 m/s is 44.7 mph, and a hurricane-force wind of 33 m/s is 73.8 mph.
Why 2.2369
A mile is 1,609.344 metres and an hour is 3,600 seconds, so one m/s is 3,600 divided by 1,609.344 miles per hour, which is 2.2369. The factor is exact, so no rounding enters the conversion.
A quick sanity test
The mph figure is a little more than double the m/s figure. If a “convert m/s to mph” calculation result is smaller than the starting number, you divided instead of multiplying.
The metre per second
The Nordic wind unit
The metre per second is the SI unit of speed. Meteorological institutes in northern Europe, as well as many research organisations, express wind in it. Forecast apps for the region default to m/s, and gust values often appear next to the average.
Where it appears
Nordic forecasts, scientific papers, buoy data and research models.
The mile per hour
The American wind unit
The mile per hour is the unit of wind in American forecasts and warnings. The National Weather Service defines wind advisories, high-wind warnings and hurricane categories in mph, so the thresholds come with the unit.
Where it appears
US weather forecasts, warnings, hurricane advisories and local news.
The two units side by side
One m/s is 2.237 mph, so a figure in mph runs a little over twice the figure in m/s. A Nordic wind of 10 m/s feels like 22 mph, a strong breeze, while a gale of 20 m/s reads as an American 45. The scales share a shape but not their numbers, so a forecast can look mild to an American eye until the conversion is done.
The factor is exact and introduces no rounding. The only trap is direction: from m/s to mph the number grows.
Where the conversion shows up
The Beaufort scale in mph
Force 4, a moderate breeze, is 5.5 to 7.9 m/s, which is 12 to 18 mph. Force 6, a strong breeze, is 10.8 to 13.8 m/s, or 24 to 31 mph. Force 8, a gale, is 17.2 to 20.7 m/s, or 38 to 46 mph. Force 10, a storm, is 24.5 to 28.4 m/s, or 55 to 63 mph. Force 12, a hurricane, begins at 32.7 m/s, which is 73 mph. A “convert m/s to mph” calculation turns any Nordic forecast into a Beaufort force.
US wind warnings
The National Weather Service issues a wind advisory for sustained winds of about 31 to 39 mph, which is 13.9 to 17.4 m/s, or gusts of 46 to 57 mph, which is 20.6 to 25.5 m/s. A high wind warning is for sustained winds of 40 mph or more, which is 17.9 m/s, or gusts of 58 mph or more, which is 25.9 m/s. The numbers differ by region.
Hurricanes and tornadoes
A category 1 hurricane has sustained winds of 74 to 95 mph, which is 33 to 42.5 m/s. Category 3 is 111 to 129 mph, or 50 to 58 m/s, and category 5 is 157 mph or more, or 70 m/s. An EF2 tornado is 111 to 135 mph, or 50 to 60 m/s, and an EF5 above 200 mph, or 89 m/s.
Reading a Norwegian forecast
Norwegian forecasts show wind as arrows with a speed in m/s. "Frisk bris", fresh breeze, is 8 to 10.7 m/s, which is 18 to 24 mph. "Liten kuling", a small gale, is 10.8 to 13.8 m/s, which is 24 to 31 mph. "Full storm" is 24.5 to 28.4 m/s, which is 55 to 63 mph. The names are Beaufort terms, and the speeds can be converted at a glance with a “convert m/s to mph” calculation.
Buoys and the sea
Ocean buoys report wind in m/s, and NOAA lists them in knots. A buoy reading of 15 m/s is 33.6 mph and 29 knots. Wave height depends on wind speed, duration and fetch: a steady 15 m/s wind over a long fetch builds waves of several metres, which is many feet. Sailors read both units.
Trees and buildings
Branches break at gusts around 20 m/s, which is 45 mph, and trees are uprooted at 25 to 30 m/s, or 56 to 67 mph. Roofs begin to fail around 30 m/s, or 67 mph, if poorly attached. These thresholds are used in storm damage studies, which report wind in m/s in Europe and mph in the US.
Wildfire weather
Fire managers watch wind closely. At 5 m/s, which is 11 mph, a grass fire spreads steadily, and at 10 m/s, or 22 mph, it can outrun a person. Red flag warnings in the US are issued when sustained wind reaches about 20 mph, which is 9 m/s, with low humidity. Scandinavian summers are drier now, and the same rules apply.
Pollen and air quality
Wind carries pollen and pollution. At 2 m/s, which is 4.5 mph, pollutants stay near their source, while at 6 m/s, or 13.4 mph, they disperse widely. Air quality bulletins mention wind in m/s in Europe and mph in the US. A “convert m/s to mph” calculation helps an allergy sufferer compare forecasts when travelling.
Spreadsheet formulas
Place wind speeds in m/s in column A and use =A2*2.23694 in column B. For the reverse, use =B2*0.44704. Add a column that looks up the Beaufort force. Label every column with its unit, and use one decimal.
Rounding and precision
The factor is exact: 10 m/s is 22.369 mph. Forecasts give wind to the nearest whole unit, so 22 mph is enough. For a gust of 17.9 m/s, a round 40 mph conveys the meaning, and the exact figure of 40.04 is more than the data support.
A mental shortcut
Double the m/s figure and add 12 per cent of the double. For 10 m/s: 20 plus 2.4 gives 22.4 mph. For 15 m/s: 30 plus 3.6 gives 33.6 mph. For 25 m/s: 50 plus 6 gives 56 mph. The shortcut is exact to within a tenth of a mile per hour, and it is easy to do while reading a forecast.
Landmarks to memorise
5 m/s is 11 mph, 10 m/s is 22 mph, 15 m/s is 34 mph, 20 m/s is 45 mph, 25 m/s is 56 mph, 30 m/s is 67 mph and 33 m/s is 74 mph, the hurricane threshold. With these landmarks, you can judge any Nordic forecast.
Reference ladder
1 m/s is 2.2 mph. 3 m/s is 6.7 mph. 8 m/s is 17.9 mph. 12 m/s is 26.8 mph. 17 m/s is 38 mph. 24 m/s is 53.7 mph. 30 m/s is 67.1 mph. 40 m/s is 89.5 mph. 50 m/s is 111.8 mph. A ladder like this speeds up a check.
Checking by reversing
To check any convert m/s to mph result, multiply it by 0.447. If 10 m/s became 22.4 mph, then 22.4 times 0.447 is 10.0. A second test is the size: the mph figure should be a little more than twice the m/s figure.
Hiking in the mountains
Mountain weather changes fast. A wind of 10 m/s, which is 22 mph, makes walking along an exposed ridge tiring, and 15 m/s, or 34 mph, makes it risky. Above 20 m/s, or 45 mph, hikers are advised to turn back. The same wind at the summit may be double the valley figure, so mountain forecasts list wind at different heights.
Relation to km/h and knots
1 m/s is 3.6 km/h, 1.944 knots and 2.237 mph. A wind of 15 m/s is 54 km/h, 29 knots and 33.6 mph. European forecasts use km/h on television, m/s in data, and aviation uses knots. A visitor who knows three of the four numbers can check the fourth.
Gusts and sustained wind
Forecasts give an average wind and a gust. A mean of 10 m/s, or 22 mph, can come with gusts of 16 m/s, or 36 mph. Warnings use gusts for damage and the mean for conditions at sea. Always convert the value a warning refers to, not the one at the top of a forecast table.
Wind from a different height
Wind speed rises with height. A standard measurement at 10 m above ground reads 8 m/s, which is 17.9 mph. At 100 m, where a turbine hub sits, it may be 11 m/s, or 24.6 mph. Reports mention the height, and without it a number is hard to use. Convert the unit, but do not forget the height.
Putting it together
A morning forecast says: "Northwest 12 m/s, gusts 19 m/s, falling to 8 m/s in the evening." Converted: 26.8 mph with gusts of 42.5 mph, falling to 17.9 mph. In US terms that is close to a wind advisory in the morning, easing to a fresh breeze by evening. A “convert m/s to mph” calculation for each number lets you plan the day.
Lakes, fjords and local winds
Fjords funnel wind, and local gusts can be much stronger than a general forecast suggests. A wind of 12 m/s outside the fjord, which is 27 mph, can become 20 m/s inside, which is 45 mph, where the valley narrows. Visitors who rent kayaks or boats are advised to check local warnings, and a “convert m/s to mph” calculation on each number shows when conditions pass the limit of a beginner.
Northern lights trips and winter driving
Aurora tours in northern Norway and Finland run in winter, with wind forecasts of 5 to 15 m/s, or 11 to 34 mph. Strong wind and snow can close mountain passes, and convoys may be organised. Drivers from the US should know that 15 m/s, or 34 mph, with snow means poor visibility, even if the temperature feels bearable.
Ferries and small boats
Coastal ferries in Norway may cancel at winds of 20 m/s, which is 45 mph, depending on the route. Small boats stay ashore from about 10 m/s, which is 22 mph. Visitors who see "kuling" on a timetable board should read it as 14 to 21 m/s, or 31 to 47 mph, and expect rough water.
Flying and drones
A small aircraft pilot treats a crosswind of 8 m/s, which is 18 mph, as challenging. Light drones are limited to about 10 m/s, or 22 mph, and many to 8 m/s, or 18 mph. An American pilot reading a European forecast needs the conversion before deciding, and aviation reports use knots, which sits between the two.
Camping and tents
A typical three-season tent holds up to about 15 m/s, or 34 mph, when pitched well. Mountain tents are rated to 25 to 30 m/s, or 56 to 67 mph. Guy lines, orientation and sheltered spots matter more than the rating. Forecasts for camp sites in Scandinavia use m/s, and a quick convert m/s to mph tells you whether to pitch the tent or find a hut.
Cycling in the wind
A headwind of 5 m/s, which is 11 mph, slows a cyclist who rides 25 km/h on the flat to roughly 15 km/h at the same effort. A tailwind of the same strength speeds the rider up by a similar amount. Cycling routes along the coast of Denmark and the Netherlands are known for steady winds of 5 to 8 m/s, or 11 to 18 mph, which is why riders plan routes into the wind first.
Wind chill
Wind makes cold feel colder. At minus 5 °C, a wind of 10 m/s, which is 22 mph, gives a feels-like temperature near minus 13 °C. The American wind chill index uses mph and Fahrenheit, while the Nordic one uses m/s and Celsius. A visitor must convert both the wind and the temperature to compare the readings.
Snow and blizzards
Blowing snow begins at about 7 m/s, which is 16 mph, and a blizzard needs strong wind, low visibility and falling or blowing snow for three hours. In US terms the wind criterion is sustained 35 mph, which is 15.6 m/s. Nordic road authorities close mountain roads when wind exceeds 15 to 20 m/s, or 34 to 45 mph, during snowfall.
Wind energy
Wind turbines produce at winds from 3 m/s, which is 6.7 mph, and reach full power near 12 m/s, which is 26.8 mph. They shut down at 25 m/s, or 55.9 mph, for safety. The power of the wind rises with the cube of speed, so a wind of 12 m/s carries 64 times the power of 3 m/s. American data on wind power are often in mph, and a “convert m/s to mph” calculation reconciles European specifications.
More values for convert m/s to mph
A longer list of conversions
If the value you need is not in the first list, these further conversions may be close enough to read off directly:
- 0.1 m/s = 0.223694 mph
- 0.5 m/s = 1.11847 mph
- 3 m/s = 6.71081 mph
- 4 m/s = 8.94775 mph
- 7 m/s = 15.6586 mph
- 15 m/s = 33.554 mph
- 20 m/s = 44.7387 mph
- 75 m/s = 167.77 mph
- 200 m/s = 447.387 mph
- 500 m/s = 1,118.47 mph
- 2,000 m/s = 4,473.87 mph
- 10,000 m/s = 22,369.4 mph
Common slips when you convert m/s to mph
Dividing instead of multiplying
From m/s to mph the number grows. If 10 m/s became 4.5, you divided.
Using 3.6
3.6 converts m/s to km/h. For mph the factor is 2.2369.
Mixing gusts and averages
Convert the value that a warning mentions. Gusts are bigger than the mean.
Quick questions
What is the method for a “convert m/s to mph” calculation?
Multiply the m/s value by 2.2369.
What is 10 m/s in miles per hour?
22.4 mph.
What is 20 m/s in miles per hour?
44.7 mph.
What is 1 mph in m/s?
0.447 m/s.
Is my figure stored or sent?
No, it stays on your device.
Where to go next
Other speed tools are listed here: Convert m/s to c, Convert m/s to ft/s, Convert knots to mph, Convert km/h to mph, Convert mph to Mach, Convert km to mi, Convert mi to km, Convert °C to °F, Convert °F to °C. For the opposite direction, use Convert mph to m/s.
The takeaway: a “convert m/s to mph” calculation multiplies by 2.2369 and labels the result mph. The figure you enter is processed on your device only.