miles per hour

Physical unit
Unit name	miles per hour
Unit symbol	${\displaystyle \mathrm {mph} }$ or ${\displaystyle \mathrm {mi/h} }$
Physical quantity (s)	speed
dimension	${\displaystyle {\mathsf {L\;T^{-1}}}}$
system	Anglo-American system of measurement
In SI units	${\displaystyle \mathrm {1\,mph=0{,}447\,04\,{\frac {m}{s}}} }$
Derived from	Statute Mile , hour

Mph ( miles per hour , just mph ) is a unit of speed . Despite the official abbreviation mi for mile (s), this value is rarely given as 'mi / h', except in technical publications.

An object that moves at 1 mph for one hour covers a distance of one mile (formerly also called English mile , country mile or statute mile ).

Speedometer with mph outside and km / h inside. Such scales are common in the United States.

use

Road traffic

The unit is used in some English-speaking countries that have not yet adopted or implemented the metric system . In the UK and US , speed is commonly reported in mph .

air traffic

Aircraft airspeed indicators usually indicate the international nautical unit knot (kn, formerly kt and plural kts) based on the longer nautical mile .

In contrast , in smaller aircraft the display is sometimes calibrated in mph , in gliders and Russian aircraft it is more likely to be given in km / h .

conversion

The conversion of miles per hour into kilometers per hour , meters per second and in knots (kn, nautical miles per hour):

${\displaystyle 1\;{\mathrm {mph} }\,=\,1{,}609344\,{\mathrm {km} \over \mathrm {h} }\,=\,0{,}44704\,{\mathrm {m} \over \mathrm {s} }\,=\,0{,}869\;\mathrm {kn} }$

The conversion in the opposite direction:

${\displaystyle 1\,{\mathrm {km} \over \mathrm {h} }\,=\,0{,}62\;{\mathrm {mph} }}$

${\displaystyle 1\,{\mathrm {m} \over \mathrm {s} }\,=\,2{,}236\;{\mathrm {mph} }}$

${\displaystyle 1\;{\mathrm {kn} }\,=\,1{,}15\;{\mathrm {mph} }}$

An easy to remember rule of thumb for converting mph to km / h is: "Times two, minus 20%". As a formula:

${\displaystyle x\;{\mathrm {mph} }\,=\,x\cdot 2\cdot 0{,}8\,{\mathrm {km} \over \mathrm {h} }}$

The error of this conversion based on the smooth factor 1.6 is a little less than 0.6%.

Individual evidence

1. ↑ tippscout.de: Convert miles to kilometers per hour