Help:Convert units

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Template {{convert}} converts a value from one unit of measurement to another. This page documents some features of units, and lists units that are commonly used in conversions.

Help:Convert • Overview
Module:Convert/documentation/conversion data • Full list of units
Help:Convert messages • Error and warning messages

This help page is a how-to guide.

It explains concepts or processes used by the Wikipedia community. It is not one of Wikipedia's policies or guidelines, and may reflect varying levels of consensus.

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H:CONUH:CONU

Default output

If no output unit is specified, the default output for the input unit will be used. Using defaults provides greater uniformity across articles.

Some options provide text that the template may mistakenly use for the output unit, if none is specified. That can be avoided by providing an empty output unit, as shown in the following examples.

{{convert|4|ft}} → 4 feet (1.2 m)
{{convert|4|ft|adj=mid|-long}} → 4-foot (^{[convert: unknown unit]})
{{convert|4|ft||adj=mid|-long}} → 4-foot-long (1.2 m)

The second of the above examples produces an error because "-long" is interpreted as the name of the output unit. The third example avoids that by specifying an empty output unit, which means "use the default."

The following also works, although it sets the output precision to 0.

{{convert|4|ft|0|adj=mid|-long}} → 4-foot-long (1 m)

The last example works because "|0" sets the output precision to zero, and convert does not look for an output unit once the precision has been specified because a precision is always given after the output unit, if any.

SI prefixes

The standard SI prefixes can applied to the following units.

More information Text, Symbol ...

Metric prefixes
Text	Symbol	Factor	or
yotta	Y	10²⁴	1000000000000000000000000
zetta	Z	10²¹	1000000000000000000000
exa	E	10¹⁸	1000000000000000000
peta	P	10¹⁵	1000000000000000
tera	T	10¹²	1000000000000
giga	G	10⁹	1000000000
mega	M	10⁶	1000000
kilo	k	10³	1000
hecto	h	10²	100
deca	da	10¹	10
(none)	(none)	1
deci	d	10⁻¹	0.1
centi	c	10⁻²	0.01
milli	m	10⁻³	0.001
micro	μ	10⁻⁶	0.000001
nano	n	10⁻⁹	0.000000001
pico	p	10⁻¹²	0.000000000001
femto	f	10⁻¹⁵	0.000000000000001
atto	a	10⁻¹⁸	0.000000000000000001
zepto	z	10⁻²¹	0.000000000000000000001
yocto	y	10⁻²⁴	0.000000000000000000000001

More information Unit type, Unit code ...

Unit type	Unit code	Unit name
Area	a	are
Area	m2	square metre
Charge	coulomb	coulomb
Energy	J	joule
Force	N	newton
Length	m	metre
Magnetic field strength	T	tesla
Mass	g	gram
Power	W	watt
Pressure	Pa	pascal
Radioactivity	Bq	becquerel
Radioactivity	Ci	curie
Time	s	second
Volume	L	litre
	l	litre
	m3	cubic metre

Some SI prefixes are demonstrated in the following. As a convenience, "micro" can be entered as "u" instead of "μ".

{{convert|1.23|Gm|angstrom}} → 1.23 gigametres (1.23×10¹⁹ Å)
{{convert|1.23|Mm|angstrom}} → 1.23 megametres (1.23×10¹⁶ Å)
{{convert|1.23|Ts|hour}} → 1.23 teraseconds (340,000,000 h)
{{convert|1.23|nJ|Wh}} → 1.23 nanojoules (3.4×10⁻¹³ Wh)
{{convert|1.23|μm|in}} → 1.23 micrometres (4.8×10⁻⁵ in)
{{convert|1.23|um|in}} → 1.23 micrometres (4.8×10⁻⁵ in)
{{convert|1.23|um|uin|abbr=on}} → 1.23 μm (48 μin)
{{convert|18|mm|in}} → 18 millimetres (0.71 in)
{{convert|18|km|mi}} → 18 kilometres (11 mi)

The above demonstrates that "uin" is the unit code for microinch.

Combinations

An input unit can be converted to any number of output units—the outputs are specified as a "combination" by separating unit codes with a space (" ") or a plus ("+"). Using a space as a separator does not work if any of the unit codes contains a space.

For example, each of the following converts 1.2 km² to acres, square yards, and hectares.

{{convert|1.2|km2|acre sqyd ha}} → 1.2 square kilometres (300 acres; 1,400,000 sq yd; 120 ha)
{{convert|1.2|km2|acre+sqyd+ha}} → 1.2 square kilometres (300 acres; 1,400,000 sq yd; 120 ha)

In the following, because "board feet" contains a space, using a space to make a combination fails.

{{convert|123|cuyd|m3 board feet}} → 123 cubic yards (^{[convert: unknown unit]})
{{convert|123|cuyd|m3+board feet}} → 123 cubic yards (94 m³; 40,000 board feet)

The following converts a pressure to four output units. The precision is 1 (1 decimal place), and units are abbreviated and linked.

{{convert|895|hPa|psi inHg atm mbar|1|abbr=on|lk=on}} → 895 hPa (13.0 psi; 26.4 inHg; 0.9 atm; 895.0 mbar)

It is preferable to use "+" to separate output units when the first unit uses engineering notation; that avoids looking up the unit in Module:Convert/extra.

{{convert|1.2|AU|e6km+e6mi|abbr=on}} → 1.2 AU (180×10^⁶ km; 110×10^⁶ mi)
{{convert|1.2|AU|e6km+e6mi|abbr=unit}} → 1.2 AU (180 million km; 110 million mi)

Some "standard" combinations have been defined—see the full list of units.

Engineering notation

Most units can be combined with a scale factor, for example, e6km represents a million kilometres. The following prefixes may be used; per WP:NUMERAL, values follow the short scale. If lk is on, the numbers are linked as shown below.

e3 (thousand)
e6 (million)
e9 (billion)
e12 (trillion)
e15 (quadrillion)

Engineering notation can only be applied to simple units—temperatures, combinations, and some other special units will not work.

Some examples using engineering notation follow.

{{convert|123.4|e3m2}} → 123.4 thousand square metres (1.328×10^⁶ sq ft)
{{convert|123.4|e3m2|e6sqft|abbr=off}} → 123.4 thousand square metres (1.328 million square feet)
{{convert|1.23|e6L}} → 1.23 million litres (320,000 US gal)
{{convert|1.23|e6L|e3usgal|abbr=off|lk=on|sp=us}} → 1.23 million liters (320 thousand U.S. gallons)
{{convert|1.23|e9impgal}} → 1.23 billion imperial gallons (5.6 Gl)
{{convert|1.23|e9impgal|e3usgal|abbr=off|lk=on}} → 1.23 billion imperial gallons (1,480,000 thousand US gallons)
{{convert|1.23|e12cuft}} → 1.23 trillion cubic feet (35×10^⁹ m³)

Units

Here are the most commonly used units. See below for hands or Mach. For rarer or historic units, see Module:Convert/documentation/conversion data#Conversions.