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 Unit Conversion Calculator
Conversion Result
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 | m/s | km/h | mph | knots |
|---|---|---|---|---|
| Highway speed | 25-33.3 m/s | 90-120 km/h | 55-75 mph | 48.6-64.8 knots |
| Walking speed | 1.4 m/s | 5 km/h | 3.1 mph | 2.7 knots |
| Running speed | 4.2 m/s | 15 km/h | 9.3 mph | 8.1 knots |
| Speed of sound | 343 m/s | 1235 km/h | 767 mph | 667 knots |
| 1 m/s | 1 m/s | 3.6 km/h | 2.24 mph | 1.94 knots |
| 1 km/h | 0.28 m/s | 1 km/h | 0.62 mph | 0.54 knots |
| 1 mph | 0.45 m/s | 1.61 km/h | 1 mph | 0.87 knots |
Angular Speed Conversions
| Angular Speed | rad/s | RPM | °/s |
|---|---|---|---|
| 1 rad/s | 1 rad/s | 9.55 RPM | 57.3 °/s |
| 1 RPM | 0.105 rad/s | 1 RPM | 6 °/s |
| 1 °/s | 0.017 rad/s | 0.167 RPM | 1 °/s |
Speed Conversion Applications
Transportation
- Vehicle speed limit conversions for international travel
- Automotive engineering specifications and testing
- Traffic management and planning
Aviation & Marine
- Aircraft speed measurements (ground speed vs. air speed)
- Navigation calculations for ships and boats
- Weather impact assessment (wind speeds)
Science & Research
- Physics experiments involving motion and velocity
- Fluid dynamics and aerodynamics testing
- Meteorological studies of atmospheric movement
Sports & Athletics
- Performance analysis in running, cycling, swimming
- Ball speed measurement in various sports
- Race timing and speed tracking
Educational Resource
This educational video from The Organic Chemistry Tutor explains how to convert between different units using conversion factors, with clear examples including speed unit conversions.
Speed Conversion Resources
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.
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Speed Conversion FAQs
Find answers to common questions about speed measurements and conversions.