Speed Unit Info

Common speed units:

  • Meter per second (m/s): SI unit
  • Kilometer per hour (km/h): common
  • Mile per hour (mph): US & UK
  • Knot (kn): marine & aviation
  • Foot per second (ft/s): engineering

Key relationships:

  • 1 m/s = 3.6 km/h = 2.237 mph
  • 1 km/h = 0.278 m/s = 0.621 mph
  • 1 mph = 0.447 m/s = 1.609 km/h
  • 1 knot = 1.852 km/h = 1.151 mph

Miles per hour:

Developed in the UK and US as a natural extension of the mile measurement. Became standardized in the 17th-18th centuries and was widely adopted for road transportation.

Meters per second:

Introduced as part of the metric system during the French Revolution. It is the SI unit for speed and is widely used in scientific and engineering applications.

Knots:

Originated from maritime navigation where sailors measured speed by counting knots in a rope paid out behind a ship. One knot equals one nautical mile per hour.

Kilometers per hour are used for:

  • Road speed limits (most countries)
  • Vehicle speedometers (metric countries)
  • Weather reports (wind speed)
  • Sports (running, cycling, etc.)

Miles per hour are used for:

  • Road speeds (US, UK, some others)
  • Vehicle specifications in non-metric countries
  • Sports timing in imperial countries

Other units:

  • Knots: aviation and marine navigation
  • Meters per second: physics and engineering
  • Mach: aviation (ratio to speed of sound)

Speed Conversion Calculator

Conversion Result

1 ft/s=
1.000 km/h

Use the converter above to calculate different values and units

What are Speed Measurements?

Speed measurements quantify the rate of change in position of an object, expressed as distance traveled per unit of time. There are several systems for measuring speed, with meters per second, kilometers per hour, and miles per hour being the most common.

The relationship between these units is precisely defined: 1 m/s = 3.6 km/h = 2.237 mph = 1.944 knots. This relationship is fundamental in physics, engineering, transportation, navigation, and many other fields.

Learn more from NIST or Bureau International des Poids et Mesures (BIPM).

Common Speed Conversions

Speed conversions are essential in transportation, aviation, marine navigation, physics, engineering, and sports. They enable precise calculations across different measurement systems and are fundamental to understanding motion and velocity.

Speed Conversion Applications

Speed conversions are essential in transportation, aviation, marine navigation, physics, engineering, and sports. They enable precise calculations across different measurement systems and are fundamental to understanding motion and velocity.

Educational Resource

This educational video explains how to convert between different units using conversion factors, with clear examples including speed unit conversions.

Speed Conversion Resources

Download Speed Conversion Chart (PDF)

Get our comprehensive speed conversion chart showing meters per second, kilometers per hour, miles per hour and other velocity units for quick reference when you're working with speed measurements.

Speed Conversion FAQs

Find answers to common questions about speed measurements and conversions.