How to use
New Tools: Sunrise, Sunset, Day Length, Local Time around the World - over 200,000 cities around the World, e.g. Sunrise in NYC today, Local Time in Tokyo, Japan
Accuracy - number of significant decimal digits:
Displays link url to your conversion.
50 km/h = 31 mph
Speed limit in built-up areas in most countries of Europe (Poland - 60 km/h, UK - 48 km/h)
90 km/h = 56 mph
Speed limit outside built-up areas in most countries of EU (European Union)
130 km/h = 80 mph
Speed limit on motorways (highways) in most countries of Europe
Speed of sound travel
The speed of sound depends on the properties of the medium through which it travels. In dry air at 59°F (15°C) at the sea level it is equal to 1 Ma (Mach 1 = 1225km/h = 761mph)
Earth Escape Velocity
Escape Velocity is the speed needed to "break free" from a gravitational field of the object (Earth, Sun etc.). The speed needed to leave gravitational field of the Earth is about 11.19 km/s = 25031 mph
Speed Of Light Travel
The speed of light depends on the properties of the medium through which it travels. For example, speed of light in water equals about 3/4 of c. The speed of the light in perfect vacuum equals c = 299,792,458 m/s = 670,616,629 mph
Usain Bolt Record - 100m sprint race
August 16, 2009 Berlin Atletic Championship - Usain Bolt breaks his own world record. He ran 100m in 9.58 seconds !!!. His average speed was 10.4384 m/s.
Previous record: Usain Bolt is the current world record holder in the 100m sprint race - 9.69 seconds. The record has been established August 16,2008 during Beijing Summer Olympic Games. His average speed during the race equals 10.3199 m/s
Fastest land animal speed
Cheetah (Acinonyx jubatus) is the fastest land animal, reaching speed up to 120 kilometres per hour (75 mph)
Space Shuttle On Re-entry
Typical space shuttle on its way back to earth on its way back to Earth during atmospheric reentry is about 17,500mph
Usain Bolt Record - 200m sprint race
August 20, 2009 Berlin Atletic Championship - Usain Bolt breaks his own world record. He ran 200m in 19.19 seconds !!!. His average speed was 10.4221 m/s.
Previous: Current record holder in 200m sprint is Usain Bolt. The record has been broken August 20,2008 during Summer Olympic Games in Beijing (China). Bolt run 19.30 seconds.
Usain Bolt speed during the 200m sprint race : 10.3627 m/s.
Note, average speed in this race was faster then 100m sprint race speed (10.3199 m/s)
Michael Johnson Record
The current world record holder of the 400 m sprint race is Michael Johnson, USA. The record has been broken August 26, 1999 in Seville, Spain. Johnson ran 43.18s.
His average speed during the winning 400m race: 9.2635 m/s
mph vs. kph (km/h) Example
If your speed or velocity is given in miles per hour (mph) and you want to translate it into kilometers per hour (km/h) type your mph value into edit box labeled 'miles per hour'. Convertion will start automatically as you type, translated value in km/h will be displayed in the edit box labeled 'Kilometers per hour'. On the other hand, km/h to mph conversion starts when you type value of km/h in the edit box labeled 'kilometers per hour'.
Fundamental unit of speed in the International System Of Units (SI) is:
meter per second [m/s].
All our online converters are free to use. We try to keep our software free of bugs and errors but we do not take any responsibility for any problems caused through the use of these calculators and converters.