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 second?

Kilometre per second is a unit of speed equal to 1,000 metres per second. It is used in astrophysics, rocket propulsion, and the measurement of planetary and cosmic velocities.

Real-world uses

Kilometres per second is used in astronomy and astrophysics for orbital velocities, galaxy recession speeds, and asteroid approach velocities. Earth orbits the Sun at about 29.78 km/s, and escape velocity from Earth is about 11.2 km/s.

History

Kilometres per second became a standard unit in celestial mechanics and astrophysics during the 20th century. It provides convenient numbers for solar system velocities, while larger cosmic speeds are often expressed as fractions of the speed of light.

Common mistakes

Forgetting the enormous scale—1 km/s = 3,600 km/h. A common error is treating km/s figures as if they were km/h. Also, confusing orbital speed with escape velocity, which are related but different concepts.

When is this conversion used?

Converting centimetre per second to kilometre per second is useful in the speed domain when comparing values across different measurement standards or applying formulas that require a specific unit.

Worked examples

1 centimetre per second = 0.00001 kilometre per second

1 kilometre per second = 1,000 metre per second

How to convert centimetre per second to kilometre per second

To convert centimetre per second to kilometre per second, multiply the value by 0.00001.

To convert kilometre per second back to centimetre per second, multiply by 100,000.

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 second

centimetre per second	kilometre per second
0.1	0.000001
0.5	0.000005
1	0.00001
2	0.00002
5	0.00005
10	0.0001
25	0.00025
50	0.0005
100	0.001
250	0.0025
500	0.005
1,000	0.01

Common values

	centimetre per second	kilometre per second
Walking speed	140 centimetre per second	0.0014 kilometre per second
City speed limit	1,390 centimetre per second	0.0139 kilometre per second
Highway driving	3,130 centimetre per second	0.0313 kilometre per second
Commercial aircraft	25,000 centimetre per second	0.25 kilometre per second
Speed of sound (sea level)	34,029 centimetre per second	0.34029 kilometre per second

Available Speed units

More centimetre per second conversions

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