Kilometers per hour to meters per second (km/h to m/s) converter

What is a kilometers per hour to meters per second converter?

A kilometers per hour to meters per second converter is an online tool that translates a speed expressed in kilometers per hour (km/h) into its equivalent in meters per second (m/s), and back again. Kilometers per hour is the everyday unit you see on road signs, car speedometers, and weather reports, while meters per second is the coherent SI unit of speed used throughout physics, engineering, and scientific work. The converter removes the mental arithmetic from switching between the two, so a familiar driving speed can be expressed in the units a calculation or formula actually expects.

How does the converter work?

Both km/h and m/s describe the same physical quantity: distance travelled divided by time elapsed. They differ only in the size of the distance unit and the time unit. One kilometer equals 1,000 meters, and one hour equals 3,600 seconds. Dividing 1,000 by 3,600 gives the single number that links the two scales: 1 km/h equals exactly 1/3.6 m/s.

Enter a value in either field and the converter instantly fills in the other. Type a road speed in km/h to read it in m/s, or type an m/s figure from a physics problem to see the equivalent km/h. The fields are linked in both directions, so you never have to decide in advance which way you are converting. The selectors also let you compare against related speed units such as miles per hour (mi/h), knots, and feet per second (ft/s).

Formula for conversion

To convert kilometers per hour to meters per second, divide by 3.6 (equivalently, multiply by 1,000 and divide by 3,600):

$\text{m/s} = \frac{\text{km/h}}{3.6}$

To convert meters per second back to kilometers per hour, multiply by 3.6:

$\text{km/h} = \text{m/s} \times 3.6$

For reference, the related unit miles per hour converts to meters per second using:

$\text{m/s} = \text{mi/h} \times 0.44704$

Conversion table

The following table lists common speeds in kilometers per hour and their equivalents in meters per second, rounded to a practical number of decimals:

Examples

Example 1: 1 km/h to m/s

Convert a single kilometer per hour to meters per second by dividing by 3.6:

$\frac{1}{3.6} = 0.27778 \text{ m/s}$

So 1 km/h is about 0.27778 m/s.

Example 2: 1 m/s back to km/h

Going the other way, multiply 1 meter per second by 3.6:

$1 \times 3.6 = 3.6 \text{ km/h}$

A speed of 1 m/s therefore equals exactly 3.6 km/h.

Example 3: A highway speed of 100 km/h

To express a typical highway speed of 100 km/h in meters per second, divide by 3.6:

$\frac{100}{3.6} = 27.7778 \text{ m/s}$

A car travelling at 100 km/h covers roughly 27.78 meters every second.

Example 4: 1 mi/h to m/s

If your source speed is in miles per hour, select mi/h as the input unit. One mile per hour equals 0.44704 m/s:

$1 \times 0.44704 = 0.44704 \text{ m/s}$

Notes

• The factor 3.6 is exact, because 1 km = 1,000 m and 1 h = 3,600 s. No rounding is hidden in the conversion itself; any rounding you see is only in the displayed result.
• A quick mental shortcut: to estimate m/s from km/h, divide by about 3.6, or for a rough figure divide by 4 and add a little back.
• Meters per second is the SI unit, so it is the natural choice when plugging speed into physics formulas such as kinetic energy or distance equals speed times time.
• Use the unit selectors to compare against miles per hour, knots, or feet per second when working with mixed sources.

Frequently asked questions

How do I convert km/h to m/s?

Divide the speed in kilometers per hour by 3.6. For example, 90 km/h divided by 3.6 equals 25 m/s.

How many meters per second is 1 km/h?

One kilometer per hour equals approximately 0.27778 meters per second, found by dividing 1 by 3.6.

How do I convert m/s back to km/h?

Multiply the speed in meters per second by 3.6. For instance, 10 m/s multiplied by 3.6 equals 36 km/h.

What is 100 km/h in m/s?

A speed of 100 km/h equals about 27.78 m/s, since 100 divided by 3.6 is 27.7778. If you want to compare road speeds across different units, our speed converter handles several units at once.

Why is the conversion factor exactly 3.6?

Because one kilometer is 1,000 meters and one hour is 3,600 seconds. Dividing 3,600 by 1,000 gives 3.6, the exact ratio between the two units.

Is meters per second the same as the SI unit of speed?

Yes. Meters per second is the coherent SI unit of speed, which is why physics and engineering calculations almost always use m/s rather than km/h.