What this calculator does
Converting m/s to km/h is a fixed multiplication: multiply by 3.6. That factor comes directly from the definitions of the units involved, 3,600 seconds in an hour divided by 1,000 metres in a kilometre, so it is exact rather than approximate.
Metres per second is the standard scientific unit for speed, used throughout physics, while kilometres per hour is the everyday unit most people read off a speedometer or a weather report. This calculator converts between the two in either direction, with the equivalent in miles per hour shown as well.
The formula
To go from m/s to km/h, multiply by 3.6. To go the other way, from km/h to m/s, divide by 3.6. The factor is exact: it falls straight out of converting 1,000 metres to 1 kilometre and 3,600 seconds to 1 hour.
| Term | Meaning |
|---|---|
| m/s | Metres per second: the SI unit of speed, distance travelled per second. |
| km/h | Kilometres per hour: distance travelled per hour, the common everyday speed unit. |
| 3.6 | The exact conversion factor: 3,600 seconds per hour ÷ 1,000 metres per kilometre. |
The inputs explained
| Field | What to enter |
|---|---|
| Value | The speed value to convert. |
| Convert | Whether you are converting m/s to km/h, or km/h to m/s. |
When to use it
Reading a physics problem into everyday units
Physics problems and calculations typically work in m/s, but the result is often more meaningful expressed as km/h, the unit a speedometer or a weather bulletin actually uses.
Converting wind speed or scientific data
Wind speed, current speed and other scientific measurements are often recorded in m/s, and converting to km/h makes them directly comparable to everyday driving or weather speeds.
Checking a top speed or terminal velocity figure
Falling-object and terminal-velocity problems, along with sprint and athletics timing, are commonly quoted in m/s and are easier to picture once converted to km/h.
Worked examples
Every figure in the tables below is produced by this page’s own calculator at build time, so the numbers and the tool always agree. Select any row to load that scenario.
m/s to km/h at common speeds
A range of m/s values converted to km/h and mph.
| m/s | Kilometres per hour | In miles per hour |
|---|---|---|
| 1 m/s | 3.60 km/h | 2.24 mph |
| 5 m/s | 18.00 km/h | 11.18 mph |
| 10 m/s | 36.00 km/h | 22.37 mph |
| 20 m/s | 72.00 km/h | 44.74 mph |
| 30 m/s | 108.00 km/h | 67.11 mph |
| 33.33 m/s | 119.99 km/h | 74.56 mph |
km/h to m/s at common road speeds
A range of km/h speed-limit style values converted to m/s and mph.
| km/h | Metres per second | In miles per hour |
|---|---|---|
| 10 km/h | 2.778 m/s | 6.21 mph |
| 30 km/h | 8.333 m/s | 18.64 mph |
| 50 km/h | 13.889 m/s | 31.07 mph |
| 60 km/h | 16.667 m/s | 37.28 mph |
| 100 km/h | 27.778 m/s | 62.14 mph |
| 110 km/h | 30.556 m/s | 68.35 mph |
Questions
What is the formula to convert m/s to km/h?
Multiply the m/s value by 3.6. For example, 10 m/s × 3.6 = 36 km/h. The factor is exact, derived directly from the definitions of the metre, kilometre, second and hour.
How do I convert km/h back to m/s?
Divide the km/h value by 3.6. For example, 36 km/h ÷ 3.6 = 10 m/s.
Why is 3.6 the exact conversion factor?
There are 1,000 metres in a kilometre and 3,600 seconds in an hour. Converting metres per second to kilometres per hour multiplies by 3,600 (seconds to hours) and divides by 1,000 (metres to kilometres), which simplifies to a single multiplication by 3.6.
Is m/s or km/h used in physics?
Metres per second is the SI unit and the one used in physics formulas and calculations. Kilometres per hour is a derived, everyday unit that is usually only used for reporting a result in a more familiar form.
For speeds given in knots rather than m/s, see the knots to km/h converter. For a length conversion at a very different scale, see the nanometres to metres converter.