What is metre per second?

Metre per second is the SI unit of speed. It is used in physics, engineering, and scientific contexts to express velocity, and serves as the reference unit for all speed calculations in this converter.

Real-world uses

Metres per second is the SI unit of speed used in physics, engineering, and scientific research. Wind speed in meteorological data, projectile velocities, and fluid flow rates are expressed in m/s. The speed of sound at sea level is approximately 343 m/s.

History

As an SI derived unit, metres per second became the standard scientific speed unit with the adoption of the SI system in 1960. It naturally combines the base units of length (metre) and time (second).

Common mistakes

Forgetting to convert from km/h—divide by 3.6, not by 3.0 or 60. Also, confusing velocity (vector with direction) with speed (scalar magnitude), both expressed in m/s but with different physical meanings.

What is kilometre per hour?

Kilometre per hour is a unit of speed equal to one kilometre travelled in one hour. It is the most widely used unit for road speed limits, vehicle speedometers, and wind speeds in metric countries.

Real-world uses

Kilometres per hour is the standard speed unit for road traffic in most countries, displayed on car speedometers, speed limit signs, and GPS devices. Weather services report wind speeds in km/h, and athletes track running pace in min/km.

History

Kilometres per hour became widespread as the metric system was adopted for road transport in the 20th century. The first metric speed limits appeared in continental Europe. Today, km/h is used in about 91% of the world's countries for traffic regulation.

Common mistakes

Confusing km/h with m/s—100 km/h is about 27.78 m/s, not 100 m/s. Also, when converting to mph, people often use a rough factor of 1.5 instead of the correct 1.609, leading to inaccurate speed comparisons.

When is this conversion used?

Speed limits, vehicle speedometers, and weather reports for wind speeds use different units depending on the country, making km/h to mph conversion one of the most practical speed conversions.

Worked examples

1 metre per second = 3.6 kilometre per hour

1 kilometre per hour = 0.27777778 metre per second

How to convert metre per second to kilometre per hour

To convert metre per second to kilometre per hour, multiply the value by 3.6.

To convert kilometre per hour back to metre per second, multiply by 0.27777778.

Measurement standards

The SI unit of speed is metres per second (m/s), a derived unit requiring no independent definition. The knot is defined as exactly one nautical mile (1,852 metres) per hour and is sanctioned for maritime and aeronautical navigation by the International Civil Aviation Organization.

Did you know?

The fastest human-made object is the Parker Solar Probe, which reached 635,266 km/h (about 176 km/s) in 2024 during a close pass of the Sun — fast enough to travel from New York to Tokyo in under a minute.

Quick reference: metre per second to kilometre per hour

metre per second	kilometre per hour
0.1	0.36
0.5	1.8
1	3.6
2	7.2
5	18
10	36
25	89.99999999
50	179.99999999
100	359.99999997
250	899.99999993
500	1,799.99999986
1,000	3,599.99999971

Common values

	metre per second	kilometre per hour
Walking speed	1.4 metre per second	5.04 kilometre per hour
City speed limit	13.9 metre per second	50.04 kilometre per hour
Highway driving	31.3 metre per second	112.67999999 kilometre per hour
Commercial aircraft	250 metre per second	899.99999993 kilometre per hour
Speed of sound (sea level)	340.29 metre per second	1,225.0439999 kilometre per hour

Available Speed units

More metre per second conversions

Assumption: Mach uses an approximate sea-level reference (about 340.29 m/s).