Miles per hour

This article is about the unit of speed. For the comic book, see MPH (comics). For other uses, see MPH.

Miles per hour (mph, m.p.h., MPH, or mi/h) is a British imperial and United States customary unit of speed expressing the number of miles travelled in one hour. It is used in the United Kingdom, the United States, and a number of smaller countries, most of which are UK or US territories, or have close historical ties with the UK or US.

miles per hour
Speedometer, indicating speed in miles per hour
General information
Unit system	Imperial, United States customary units
Unit of	speed
Symbol	mph
Conversions
1 mph in ...	... is equal to ...
km/h	1.609344
m/s	0.44704

Usage

Speed limit units on traffic signs around the world:

  Kilometres per hour (km/h)

  Miles per hour (mph)

  Both

  none known

50 mph speed limit sign in the United Kingdom

65 mph speed limit sign in the United States

Road traffic

Speed limits and road traffic speeds are given in miles per hour in the following jurisdictions:

• Antigua and Barbuda
• Bahamas^[1]
• Belize^[2]
• Dominica^[3]
• Grenada^[4]
• Liberia (occasionally)^[14]
• Marshall Islands
• Micronesia
• Palau
• Saint Kitts and Nevis^[15]
• Saint Lucia^[16]
• Saint Vincent and the Grenadines^[17]
• United Kingdom^[18]
• The following British Overseas Territories:
  • Anguilla^[19]
  • British Virgin Islands^[20][21]
  • British Indian Ocean Territory
  • Cayman Islands^[22]
  • Falkland Islands^[23]
  • Montserrat
  • Saint Helena, Ascension and Tristan da Cunha^[24]
  • Turks and Caicos Islands^[25]
• The Crown dependencies:
  • Bailiwick of Guernsey
  • Isle of Man
  • Jersey
• United States^[26]
• The following United States overseas dependencies:
  • American Samoa^[27]
  • Guam^[28]
  • Northern Mariana Islands^[29]
  • Puerto Rico
  • United States Virgin Islands^[30][31]

Rail networks

Miles per hour is the unit used on the US, Canadian and Irish rail systems.^[32][33][34] Miles per hour is also used on British rail systems, excluding trams, some light metro systems, the Channel Tunnel and High Speed 1.^[35]

Nautical and aeronautical usage

Nautical and aeronautical applications favour the knot as a common unit of speed. (One knot is one nautical mile per hour, with a nautical mile being exactly 1,852 metres or about 6,076 feet.)

Other usage

In some countries mph may be used to express the speed of delivery of a ball in sporting events such as cricket, tennis and baseball.

Conversions

1 mph	= 0.44704 m/s (exactly)
	= 1.609344 km/h (exactly)

Conversions between common units of speed

	m/s	km/h	mph (mi/h)	knot	fps (ft/s)
1 m/s =	1	3.600000	2.236936*	1.943844*	3.280840*
1 km/h =	0.277778*	1	0.621371*	0.539957*	0.911344*
1 mph (mi/h) =	0.44704	1.609344	1	0.868976*	1.466667*
1 knot =	0.514444*	1.852	1.150779*	1	1.687810*
1 fps (ft/s) =	0.3048	1.09728	0.681818*	0.592484*	1

(* = approximate values)

See also

• Kilometres per hour
• Acceleration
• Velocity

References

1. "The Nassau Guardian". The Nassau Guardian. Archived from the original on 26 February 2014. Retrieved 21 August 2014.
2. "Ideas and Opinions – Marijuana – another perspective - Amandala Newspaper". amandala.com.bz. 26 October 2012. Archived from the original on 18 September 2013. Retrieved 29 April 2018.
3. "Ophelia less organised but still a strong tropical storm". Dominica News Online. Archived from the original on 1 March 2014. Retrieved 21 August 2014.
4. "George Grant - TROUBLESOME FIGURES". Grenada Broadcast. 4 July 2013. Archived from the original on 1 March 2014. Retrieved 21 August 2014.
5. "Image by draperc". Mapillary. 9 September 2018. Retrieved 21 April 2019.
6. "Image by draperc". Mapillary. 9 September 2018. Retrieved 21 April 2019.
7. "Image by mkanyala". Mapillary. 11 September 2017. Retrieved 21 April 2019.
8. "Image by mkanyala". Mapillary. 11 September 2017. Retrieved 21 April 2019.
9. "Image by mkanyala". Mapillary. 11 September 2017. Retrieved 21 April 2019.
10. "Image by mkanyala". Mapillary. 11 September 2017. Retrieved 21 April 2019.
11. "Image by mkanyala". Mapillary. 11 September 2017. Retrieved 21 April 2019.
12. Joseph, Dan B. (14 April 2016). "Image by danbjoseph". Mapillary. Retrieved 21 April 2019.
13. "Image by mkanyala". Mapillary. 11 September 2017. Retrieved 21 April 2019.
14. Some signs are explicitly labeled in miles per hour,^[5] but most are either explicitly^{[6][7][8][9][10][11]} or implicitly measured in kilometers per hour.^[12][13]
15. "Businesses Close Early Due to Passage of TS Isaac". The St. Kitts-Nevis Observer. 22 August 2012. Archived from the original on 3 February 2013. Retrieved 21 August 2014.
16. "The Voice - The national newspaper of St. Lucia since 1885". Thevoiceslu.com. 1 October 2004. Archived from the original on 1 March 2014. Retrieved 21 August 2014.
17. 21 August 2014 :52 (AST) (31 October 2010). "St. Vincent appeals for aid as Tomas leaves 'millions and millions' in damage – I-Witness News". Iwnsvg.com. Archived from the original on 26 February 2014. Retrieved 21 August 2014.{{cite web}}: CS1 maint: numeric names: authors list (link)
18. Speed limits Archived 22 March 2015 at the Wayback Machine (UK) Department for Transport. Retrieved 4 August 2015
19. "Vehicles and Road Traffic Act". Government of Anguilla. 15 December 2014. Retrieved 26 March 2020.
20. "Welcome to The BVI Beacon Online". Bvibeacon.com. 1 December 2005. Archived from the original on 2 April 2015. Retrieved 21 August 2014.
21. "Road traffic (motor vehicle registration and operation, and driver and vehicle licensing) regulations, 2009 arrangement of regulations" (PDF). Government of the Virgin Islands. 20 July 2009. p. 28. Retrieved 27 April 2022.
22. "Driver exceeded critical speed of 91 mph, jury hears :: Cayman Compass". Compasscayman.com. Archived from the original on 26 February 2014. Retrieved 21 August 2014.
23. "Columns - An Islander's offerings from Essex by James Marsh". Penguin-news.com. 19 April 2012. Archived from the original on 16 October 2014. Retrieved 21 August 2014.
24. "Flying Frenchman takes off in 'overgrown pushchair' | St Helena Online". Sthelenaonline.org. 23 October 2012. Archived from the original on 1 March 2014. Retrieved 21 August 2014.
25. "Police urging motorists to slow down". Suntci.com. 15 July 2009. Archived from the original on 28 February 2014. Retrieved 21 August 2014.
26. "Modern Living: Think Metric". Time Magazine. 9 June 1975. Archived from the original on 22 January 2011. Retrieved 15 June 2010. Meanwhile, the metrication of America is already taking place. Individual federal agencies, school systems, states and industries, as well as radio announcers, supermarkets, beverage bottlers and ballpark scoreboards, are hastening the everyday use of metres, litres, and grams. ...a road sign outside Fergus Falls reads, ST. CLOUD 100 MILES OR 161 KILOMETERS. Other signs note that 55 mph equals 88 kilometres per hour.
27. "Our Traffic Problems Are Going To Get Worse". Samoa News. 3 June 2013. Archived from the original on 14 September 2013. Retrieved 21 August 2014.
28. "Maila Halom". Guampdn.com. Retrieved 21 August 2014.
29. Archived 1 March 2014 at the Wayback Machine
30. Conor Foley (Staff Writer) (6 July 2011). "Cops: Teen was driving 75 mph in city rollover crash". Virgin Islands Daily News. Archived from the original on 7 March 2014. Retrieved 21 August 2014.
31. JOY BLACKBURN (Daily News Staff) (24 August 2012). "Weather to begin clearing up today as Isaac leaves area - News". Virgin Islands Daily News. Archived from the original on 16 September 2013. Retrieved 21 August 2014.
32. "A. Classes of Track". Rules Respecting Track Safety. Transport Canada. 3 November 2008. Archived from the original on 25 August 2012. Archived 25 August 2012.
33. "Republic of Ireland". www.railsigns.uk. Retrieved 22 February 2021.
34. Rail, Irish. "Network Statement". Irish Rail. Retrieved 22 February 2021.
35. "Permanent Speed Restriction Signs". www.railsigns.uk. Retrieved 10 July 2020.