Ms To Kmh Converter
A speed of 10 m/s sounds slow, but it equals 36 km/h, which is a strong cycling pace.
Quick answer: Multiply the speed in m/s by 3.6 to get km/h. For example, 10 m/s is 36 km/h, 20 m/s is 72 km/h and 25 m/s is 90 km/h.
The m/s to km/h formula
Speed in kilometres per hour equals speed in metres per second times 3.6.
The factor 3.6 is exact, being 3,600 divided by 1,000.
Take 10 m/s. 10 × 3.6 gives 36 km/h.
Take 20 m/s. 20 × 3.6 gives 72 km/h.
Metres per second and kilometres per hour
A metre per second is the SI unit of speed, and the metre is defined from the speed of light (CASRAI: The metre). A kilometre per hour is the common road unit.
The two are linked by the number 3.6, because an hour has 3,600 seconds and a kilometre has 1,000 metres.
How to convert m/s to km/h step by step
- Write down the speed in metres per second.
- Multiply it by 3.6.
- Round to the digits you need.
- Write the unit km/h after the answer.
Example 1: 10 m/s
- Start with 10 m/s.
- 10 × 3.6 = 36.
- The speed is 36 km/h.
10 m/s = 36 km/h
Example 2: 20 m/s
- Start with 20 m/s.
- 20 × 3.6 = 72.
- The speed is 72 km/h.
20 m/s = 72 km/h
Example 3: 25 m/s
- Start with 25 m/s.
- 25 × 3.6 = 90.
- The speed is 90 km/h.
25 m/s = 90 km/h
Round only at the end. Rounding in the middle of a sum adds small errors that grow.
m/s to km/h conversion table
| metres per second (m/s) | kilometres per hour (km/h) | mph |
|---|---|---|
| 1 m/s | 3.6 km/h | 2.237 mph |
| 2 m/s | 7.2 km/h | 4.474 mph |
| 3 m/s | 10.8 km/h | 6.711 mph |
| 5 m/s | 18 km/h | 11.185 mph |
| 8 m/s | 28.8 km/h | 17.895 mph |
| 10 m/s | 36 km/h | 22.369 mph |
| 12 m/s | 43.2 km/h | 26.843 mph |
| 15 m/s | 54 km/h | 33.554 mph |
| 20 m/s | 72 km/h | 44.739 mph |
| 25 m/s | 90 km/h | 55.923 mph |
| 30 m/s | 108 km/h | 67.108 mph |
| 40 m/s | 144 km/h | 89.477 mph |
| 50 m/s | 180 km/h | 111.85 mph |
| 100 m/s | 360 km/h | 223.69 mph |
The highlighted row is the default of the calculator. The last column gives mph.
A quick mental shortcut for m/s to km/h
Triple the m/s and add 60 percent of the original. For 20 m/s, 60 + 12 = 72 km/h, which is exact.
Or multiply by 4 and take off a tenth of the result. For 25 m/s, 100 − 10 = 90 km/h.
Anchor values
5 m/s is 18 km/h, 10 m/s is 36 km/h and 20 m/s is 72 km/h. 30 m/s is 108 km/h, and 340 m/s, about the speed of sound, is 1,224 km/h.
Keep a few of these in mind to check bigger numbers fast.
More values at a glance
0.5 metres per second is 1.8 kilometres per hour. 2 metres per second is 7.2 kilometres per hour. 5 metres per second is 18 kilometres per hour.
10 metres per second is 36 kilometres per hour. 25 metres per second is 90 kilometres per hour. 100 metres per second is 360 kilometres per hour.
Each answer is the input times 3.6. You can use the same factor for any value that is not listed here.
The unit sizes
One of the metres per second equals 3.6 kilometres per hour. One of the kilometres per hour equals 0.2778 metres per second.
If a result looks very large or very small, compare it with these sizes before you use it.
Checking in reverse
Take 36 kilometres per hour and divide by 3.6. You get back 10 metres per second. If you do not, one of the numbers was typed or rounded wrongly.
More conversions in a row
0.1 metres per second is 0.36 kilometres per hour. 0.25 metres per second is 0.9 kilometres per hour. 1 metres per second is 3.6 kilometres per hour.
3 metres per second is 10.8 kilometres per hour.
7 metres per second is 25.2 kilometres per hour. 15 metres per second is 54 kilometres per hour. 40 metres per second is 144 kilometres per hour.
60 metres per second is 216 kilometres per hour.
75 metres per second is 270 kilometres per hour. 150 metres per second is 540 kilometres per hour. 200 metres per second is 720 kilometres per hour.
500 metres per second is 1,800 kilometres per hour.
Rounding the factor
The factor 3.6 is long. If you cut it to 3.6, 100 metres per second becomes 360 kilometres per hour instead of 360.
That is an error of about 0 percent, which is fine for a rough check but not for exact work.
Doubling and scaling
The conversion is a straight line through zero. Double the speed in metres per second and the speed in kilometres per hour doubles too.
So 20 metres per second is 72 kilometres per hour, and 40 metres per second is 144 kilometres per hour. You can build any value from the ones in the table.
Quick conversion answers
| Conversion | Result |
|---|---|
| 5 m/s | 18 km/h |
| 10 m/s | 36 km/h |
| 20 m/s | 72 km/h |
| 30 m/s | 108 km/h |
| 50 m/s | 180 km/h |
| 100 m/s | 360 km/h |
Where this conversion is used
Weather reports in some countries give wind in m/s while the public thinks in km/h.
Sprint speeds are often noted in m/s, and news reports quote km/h.
Common mistakes to avoid
- Dividing by 3.6. That is the km/h to m/s step.
- Using 3 as a shortcut for exact work. It is 17 percent too low.
- Mixing up the unit labels. A value of 10 with no unit is easy to misread.
- Forgetting the 3,600 seconds. A km per second is a very different unit.
Related converters
Frequently asked questions
How many kilometres per hour is 1 m/s?
1 m/s is 3.6 km/h.
How many kilometres per hour is 20 m/s?
20 m/s is 72 km/h.
How many metres per second is 1 km/h?
1 km/h is 0.2777778 m/s.
How many km/h is 1 m/s?
It is exactly 3.6 km/h.
How many km/h is 340 m/s?
It is 1,224 km/h, close to the speed of sound in air.
Is 25 m/s over 80 km/h?
Yes. 25 m/s is 90 km/h.
Sources
- CASRAI: The metre (casrai.org)
- Inch Calculator: Kilometers per Hour to Miles per Hour (inchcalculator.com)
