What is knot?

A knot is a unit of speed equal to one nautical mile per hour, approximately 1.852 km/h. It is the international standard for maritime navigation, aviation, and meteorological wind speed reporting.

Real-world uses

Knots are the universal speed unit in maritime navigation and aviation worldwide, regardless of whether a country uses metric or imperial. Ship speeds, ocean currents, wind speed in aviation weather (METAR) reports, and jet stream velocities are all given in knots.

History

The knot originates from the 17th-century practice of measuring ship speed by throwing a log overboard attached to a rope with knots tied at regular intervals. Sailors counted how many knots paid out in a fixed time (measured by a sandglass).

Common mistakes

Saying "knots per hour"—a knot already means nautical miles per hour, so adding "per hour" is redundant and incorrect. Also, confusing knots with km/h: 1 knot ≈ 1.852 km/h.

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.

When is this conversion used?

Converting between knot and centimetre per second is common when working across metric and imperial systems, such as international trade, travel between countries with different measurement standards, or following instructions from a different region.

Worked examples

1 knot = 51.44444444 centimetre per second

1 centimetre per second = 0.01 metre per second

How to convert knot to centimetre per second

To convert knot to centimetre per second, multiply the value by 51.44444444.

To convert centimetre per second back to knot, multiply by 0.01943844.

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: knot to centimetre per second

Common values

Available Speed units

• metre per second conversions
• kilometre per hour conversions
• mile per hour conversions
• knot conversions
• foot per second conversions
• metre per minute conversions
• kilometre per second conversions
• mach (approx at sea level) conversions
• centimetre per second conversions
• mile per minute conversions

More knot conversions

• Convert knot to metre per second
• Convert knot to kilometre per hour
• Convert knot to mile per hour
• Convert knot to foot per second
• Convert knot to metre per minute
• Convert knot to kilometre per second
• Convert knot to mach (approx at sea level)
• Convert knot to centimetre per second
• Convert knot to mile per minute

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