What is centimetre per second?

Centimetre per second is a unit of speed used in low-velocity applications such as biological locomotion studies, microfluidics research, and slow-moving mechanical systems.

Real-world uses

Centimetres per second is used in the CGS system for fluid flow rates, sedimentation velocities in geology, and blood flow measurements in medical Doppler ultrasound. Glacier movement and tectonic plate motion are sometimes expressed in cm/s or cm/year.

History

Centimetres per second was the standard velocity unit in the CGS (centimetre-gram-second) system, widely used in physics until the mid-20th century. While SI uses m/s, cm/s persists in certain scientific fields, particularly fluid mechanics and geophysics.

Common mistakes

Confusing cm/s with m/s by forgetting the factor-of-100 difference. Also, assuming cm/s is too small for practical use—blood flow in major arteries is typically 10–40 cm/s, which is a very practical range.

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 centimetre per second = 0.036 kilometre per hour

1 kilometre per hour = 0.27777778 metre per second

How to convert centimetre per second to kilometre per hour

To convert centimetre per second to kilometre per hour, multiply the value by 0.036.

To convert kilometre per hour back to centimetre per second, multiply by 27.77777778.

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: centimetre per second to kilometre per hour

centimetre per second	kilometre per hour
0.1	0.0036
0.5	0.018
1	0.036
2	0.072
5	0.18
10	0.36
25	0.9
50	1.8
100	3.6
250	9
500	18
1,000	36

Common values

	centimetre per second	kilometre per hour
Walking speed	140 centimetre per second	5.04 kilometre per hour
City speed limit	1,390 centimetre per second	50.04 kilometre per hour
Highway driving	3,130 centimetre per second	112.67999999 kilometre per hour
Commercial aircraft	25,000 centimetre per second	899.99999993 kilometre per hour
Speed of sound (sea level)	34,029 centimetre per second	1,225.0439999 kilometre per hour

Available Speed units

More centimetre per second conversions

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