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 mach (approx at sea level)?

Mach is a dimensionless speed unit expressing the ratio of an object’s speed to the local speed of sound. At sea level, Mach 1 is approximately 343 m/s. It is used in aviation and aerodynamics to characterise high-speed flight regimes.

Real-world uses

Mach numbers are used in aerospace engineering and aviation to describe aircraft speed relative to the speed of sound. Commercial jets cruise near Mach 0.85, military fighters reach Mach 2+, and hypersonic vehicles exceed Mach 5.

History

Named after Austrian physicist Ernst Mach, who studied supersonic projectiles in the 1880s. The Mach number was formally defined by Swiss engineer Jakob Ackeret in 1929. Chuck Yeager first broke the sound barrier (Mach 1) in 1947 in the Bell X-1.

Common mistakes

Treating Mach as a fixed speed—it varies with altitude and temperature because the speed of sound changes. Mach 1 is about 343 m/s at sea level (15°C) but about 295 m/s at 11,000 m altitude.

When is this conversion used?

Converting centimetre per second to mach (approx at sea level) 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 = 0.00002939 mach (approx at sea level)

1 mach (approx at sea level) = 340.29 metre per second

How to convert centimetre per second to mach (approx at sea level)

To convert centimetre per second to mach (approx at sea level), multiply the value by 0.00002939.

To convert mach (approx at sea level) back to centimetre per second, multiply by 34,029.

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 mach (approx at sea level)

centimetre per second	mach (approx at sea level)
0.1	0.00000294
0.5	0.00001469
1	0.00002939
2	0.00005877
5	0.00014693
10	0.00029387
25	0.00073467
50	0.00146933
100	0.00293867
250	0.00734667
500	0.01469335
1,000	0.0293867

Common values

	centimetre per second	mach (approx at sea level)
Walking speed	140 centimetre per second	0.00411414 mach (approx at sea level)
City speed limit	1,390 centimetre per second	0.04084751 mach (approx at sea level)
Highway driving	3,130 centimetre per second	0.09198037 mach (approx at sea level)
Commercial aircraft	25,000 centimetre per second	0.73466749 mach (approx at sea level)
Speed of sound (sea level)	34,029 centimetre per second	1 mach (approx at sea level)

Available Speed units

More centimetre per second conversions

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