Help:Convert units

Template:Wikipedia how-to 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

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|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.

Metric prefixes

Text	Symbol	Factor	or
yotta	Y	1024	Template:Gaps
zetta	Z	1021	Template:Gaps
exa	E	1018	Template:Gaps
peta	P	1015	Template:Gaps
tera	T	1012	Template:Gaps
giga	G	109	Template:Gaps
mega	M	106	Template:Gaps
kilo	k	103	Template:Gaps
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	Template:Gaps
nano	n	10−9	Template:Gaps
pico	p	10−12	Template:Gaps
femto	f	10−15	Template:Gaps
atto	a	10−18	Template:Gaps
zepto	z	10−21	Template:Gaps
yocto	y	10−24	Template:Gaps

Unit type	Unit code	Unit name
Area	a	are
	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
	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|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.

Area

Examples:

• {{convert|1.5|sqmi|km2}} → 1.5 square miles (3.9 km²)
• {{convert|1.5|sqmi|km2|abbr=off}} → 1.5 square miles (3.9 square kilometres)
• {{convert|1.5|sqmi|km2|abbr=on}} → 1.5 sq mi (3.9 km²)

Unit code	Unit symbol	Unit name	US name, if different
acre	acre	acre
ha	ha	hectare
m2	m2	square metre	square meter
cm2	cm2	square centimetre	square centimeter
km2	km2	square kilometre	square kilometer
sqin	sq in	square inch
sqft	sq ft	square foot
sqyd	sq yd	square yard
sqmi	sq mi	square mile

Fuel efficiency

Examples:

• {{convert|12|mpgus|km/L}} → 12 miles per US gallon (5.1 km/L)
• {{convert|12|mpgus|km/L|abbr=off}} → 12 miles per US gallon (5.1 kilometres per litre)
• {{convert|12|mpgus|km/L|abbr=off|sp=us}} → 12 miles per U.S. gallon (5.1 kilometers per liter)
• {{convert|12|mpgus|km/L|abbr=on}} → 12 mpg_‑US (5.1 km/L)

Unit code	Unit symbol	Unit name	US name, if different
km/L	km/L	kilometre per litre	kilometer per liter
mpgimp	mpg‑imp	mile per imperial gallon
mpgus	mpg‑US	mile per US gallon	mile per U.S. gallon
L/km	L/km	litre per kilometre	liter per kilometer
L/100 km	L/100 km	litre per 100 kilometres	liter per 100 kilometers

Length

Examples:

• {{convert|123|cm|in}} → 123 centimetres (48 in)
• {{convert|123|cm|in|abbr=off|sp=us}} → 123 centimeters (48 inches)
• {{convert|123|cm|in|abbr=on}} → 123 cm (48 in)

Unit code	Unit symbol	Unit name	US name, if different
uin	μin	microinch
in	in	inch
ft	ft	foot
yd	yd	yard
mi	mi	mile
nmi	nmi	nautical mile
m	m	metre	meter
cm	cm	centimetre	centimeter
mm	mm	millimetre	millimeter
km	km	kilometre	kilometer
angstrom	Å	ångström

Mass

Examples:

• {{convert|72.3|kg|lb}} → 72.3 kilograms (159 lb)
• {{convert|72.3|kg|lb|abbr=off}} → 72.3 kilograms (159 pounds)
• {{convert|72.3|kg|lb|abbr=on}} → 72.3 kg (159 lb)

Unit code	Unit symbol	Unit name	US name, if different
g	g	gram
kg	kg	kilogram
oz	oz	ounce
lb	lb	pound
st	st	stone
LT	long ton	long ton
MT	t	metric ton
ST	short ton	short ton

Pressure

Examples:

• {{convert|28|psi|Pa}} → 28 pounds per square inch (190,000 Pa)
• {{convert|28|psi|Pa|abbr=off}} → 28 pounds per square inch (190,000 pascals)
• {{convert|28|psi|Pa|abbr=on}} → 28 psi (190,000 Pa)

Unit code	Unit symbol	Unit name	US name, if different
atm	atm	standard atmosphere
mbar	mbar	millibar
psi	psi	pound per square inch
Pa	Pa	pascal

Speed

Examples:

• {{convert|60|mph|km/h}} → 60 miles per hour (97 km/h)
• {{convert|60|mph|km/h|abbr=off}} → 60 miles per hour (97 kilometres per hour)
• {{convert|60|mph|km/h|abbr=on}} → 60 mph (97 km/h)

Unit code	Unit symbol	Unit name	US name, if different
km/h	km/h	kilometre per hour	kilometer per hour
km/s	km/s	kilometre per second	kilometer per second
kn	kn	knot
mph	mph	mile per hour

Temperature

Examples:

• {{convert|100|C|F}} → 100 °C (212 °F)
• {{convert|100|C|F|abbr=off}} → 100 degrees Celsius (212 degrees Fahrenheit)
• {{convert|100|C-change|F-change}} → 100 °C (180 °F)
• {{convert|100|C-change|F-change|abbr=out}} → 100 degrees Celsius change (180 °F)

Unit code	Unit symbol	Unit name	US name, if different
C	°C	degree Celsius
F	°F	degree Fahrenheit
K	K	kelvin
C-change	°C	degree Celsius change
F-change	°F	degree Fahrenheit change
K-change	K	kelvin change

Torque

Examples:

• {{convert|12.5|Nm|lb.in}} → 12.5 newton-metres (111 lb⋅in)
• {{convert|12.5|Nm|lb.in|abbr=off}} → 12.5 newton-metres (111 pound force-inchs)
• {{convert|12.5|Nm|lb.in|abbr=on|lk=on}} → 12.5 N⋅m (111 lb⋅in)

Unit code	Unit symbol	Unit name	US name, if different
lb.in	lb⋅in	pound force-inch
lb.ft	lb⋅ft	pound force-foot
Nm	N⋅m	newton-metre	newton-meter

Volume

Examples:

• {{convert|125|cuin|l}} → 125 cubic inches (2.05 L)
• {{convert|125|cuin|l|abbr=off}} → 125 cubic inches (2.05 litres)
• {{convert|125|cuin|l|abbr=on}} → 125 cu in (2.05 L)

Unit code	Unit symbol	Unit name	US name, if different
cuin	cu in	cubic inch
cuft	cu ft	cubic foot
cuyd	cu yd	cubic yard
cumi	cu mi	cubic mile
impgal	imp gal	imperial gallon
impoz	imp fl oz	imperial fluid ounce
usgal	US gal	US gallon	U.S. gallon
usoz	US fl oz	US fluid ounce	U.S. fluid ounce
L	L	litre	liter
l	L	litre	liter
m3	m3	cubic metre	cubic meter
cc	cc	cubic centimetre	cubic centimeter
mm3	mm3	cubic millimetre	cubic millimeter

Hands (unit of length)

A hand is a unit of length used to measure the height of horses. One hand is four inches, and a value of 12.3 hands represents 12 hands + 3 inches (51 inches).

Output name

• By default, the unit is shown as a linked name (hands).
• The hands unit can be abbreviated to "h" or to "hh"; by default, abbreviations are not linked.

  {{convert|27|in|hand}} → 27 inches (6.3 hands)

  {{convert|27|in|hand|lk=off}} → 27 inches (6.3 hands)

  {{convert|27|in|hand|abbr=h}} → 27 in (6.3 h)

  {{convert|27|in|hand|abbr=hh}} → 27 in (6.3 hh)

  {{convert|27|in|hand|abbr=hh|lk=out}} → 27 in (6.3 hh)

Output value

• The hands value has at most one digit after the decimal mark, and has an optional fraction.
• A precision of 2 assumes |frac=2 (round to nearest Template:Frac inch).
• A precision of 3 or more assumes |frac=4 (round to nearest Template:Frac inch).
• If ever needed, |frac=8 can be used to round to the nearest Template:Frac inch.

  {{convert|27.63|in|hand}} → 27.63 inches (7.0 hands)

  {{convert|27.63|in|hand|0}} → 27.63 inches (7 hands)

  {{convert|27.63|in|hand|1}} → 27.63 inches (7.0 hands)

  {{convert|27.63|in|hand|2}} → 27.63 inches (6.3+1⁄2 hands)

  {{convert|27.63|in|hand|3}} → 27.63 inches (6.3+3⁄4 hands)

  {{convert|27.63|in|hand|frac=8}} → 27.63 inches (6.3+5⁄8 hands)

  {{convert|28.5|in|hand|2}} → 28.5 inches (7.0+1⁄2 hands)

  {{convert|28.5|in|hand|3}} → 28.5 inches (7.0+1⁄2 hands)

Output in hands and inches

• When using "hand in" to convert to hands and inches, the rounded hands and inches values are equivalent, and use the same fraction, if any.
• Special rounding of the inches value only occurs when "hand in" is the output. For example, if the output is "in hand", the inches value is rounded independently from the hands value.

  {{convert|156|cm|hand in}} → 156 centimetres (15.1 hands; 61 in)

  {{convert|156|cm|hand in|2}} → 156 centimetres (15.1+1⁄2 hands; 61+1⁄2 in)

  {{convert|156|cm|in hand}} → 156 centimetres (61 in; 15.1 hands)

  {{convert|156|cm|in hand|2}} → 156 centimetres (61.42 in; 15.1+1⁄2 hands)

  {{convert|156|cm|hand in|abbr=out}} → 156 centimetres (15.1 h; 61 in)

  {{convert|156|cm|hand in|abbr=h}} → 156 cm (15.1 h; 61 in)

  {{convert|156|cm|hand in|abbr=hh}} → 156 cm (15.1 hh; 61 in)

Ranges

• A range of values can be indicated with "-" (hyphen) or "to". When a dash is displayed by convert, it is always an en dash.
• Alternatively, "and" and "or" can be used.

  {{convert|137|-|156|cm|hand in}} → 137–156 centimetres (13.2–15.1 hands; 54–61 in)

  {{convert|137|-|156|cm|hand in|2}} → 137–156 centimetres (13.2–15.1+1⁄2 hands; 54–61+1⁄2 in)

  {{convert|137|-|156|cm|hand in|abbr=in}} → 137–156 cm (13.2–15.1 hands; 54–61 inches)

  {{convert|137|-|156|cm|hand in|abbr=h}} → 137–156 cm (13.2–15.1 h; 54–61 in)

  {{convert|137|-|156|cm|hand in|abbr=on}} → 137–156 cm (13.2–15.1 h; 54–61 in)

  {{convert|15000|-|20000|usgal|impgal L|abbr=on}} → 15,000–20,000 US gal (12,000–17,000 imp gal; 57,000–76,000 L)

  {{convert|137|and|156|cm|hand in|abbr=on}} → 137 and 156 cm (13.2 and 15.1 h; 54 and 61 in)

  {{convert|137|or|156|cm|hand in|abbr=on}} → 137 or 156 cm (13.2 or 15.1 h; 54 or 61 in)

Examples

• The following examples illustrate various combinations of options.

  {{convert|57|in|hand}} → 57 inches (14.1 hands)

  {{convert|2|m|hand}} → 2 metres (19.3 hands)

  {{convert|137|cm|hand|2}} → 137 centimetres (13.2 hands)

  {{convert|137|cm|hand|2|sp=us}} → 137 centimeters (13.2 hands)

  {{convert|14.1|hand|in}} → 14.1 hands (57 inches)

  {{convert|14.1|hand|cm}} → 14.1 hands (145 cm)

  {{convert|14.1|hand|in cm}} → 14.1 hands (57 inches; 145 cm)

  {{convert|14.1|hand|cm in}} → 14.1 hands (145 cm; 57 inches)

  {{convert|14.1|-|14.3|hand|cm}} → 14.1–14.3 hands (145–150 cm)

  {{convert|14.1|-|14.3|hand|in cm}} → 14.1–14.3 hands (57–59 inches; 145–150 cm)

  {{convert|50|-|57|in|hand}} → 50–57 inches (12.2–14.1 hands)

  {{convert|2|-|3|m|hand}} → 2–3 metres (19.3–29.2 hands)

  {{convert|57|or|59|in|hand|abbr=on}} → 57 or 59 in (14.1 or 14.3 h)

  {{convert|137|-|139|cm|hand|lk=on}} → 137–139 centimetres (13.2–13.3 hands)

  {{convert|137|and|162|cm|hand|0|abbr=in|lk=in}} → 137 and 162 cm (13 and 16 hands)

  {{convert|137|and|162|cm|hand in}} → 137 and 162 centimetres (13.2 and 16.0 hands; 54 and 64 in)

  {{convert|9.2|hand}} → 9.2 hands (38 inches; 97 cm)

  {{convert|9.2|hand|lk=off}} → 9.2 hands (38 inches; 97 cm)

  {{convert|9.2|hand|abbr=h}} → 9.2 h (38 in; 97 cm)

  {{convert|9.2|hand|abbr=h|lk=in}} → 9.2 h (38 in; 97 cm)

  {{convert|9.2|hand|abbr=hh|lk=in}} → 9.2 hh (38 in; 97 cm)

  {{convert|9.2+1/2|hand}} → 9.2+1⁄2 hands (38.5 inches; 98 cm)

  {{convert|9.2+3/4|hand}} → 9.2+3⁄4 hands (38.75 inches; 98 cm)

  {{convert|9.2+3/4|hand|abbr=h}} → 9.2+3⁄4 h (38.75 in; 98 cm)

  {{convert|9.2+3/4|hand|cm in}} → 9.2+3⁄4 hands (98 cm; 38.75 inches)

  {{convert|9.2+3/4|hand|cm in|abbr=out}} → 9.2+3⁄4 hands (98 cm; 38.75 in)

  {{convert|9.2+3/4|hand|cm in|abbr=on}} → 9.2+3⁄4 h (98 cm; 38.75 in)

  {{convert|9.2+3/4|hand|in}} → 9.2+3⁄4 hands (38.75 inches)

  {{convert|9.2+3/4|hand|in|abbr=out}} → 9.2+3⁄4 hands (38.75 in)

  {{convert|9.2+3/4|hand|in|abbr=on}} → 9.2+3⁄4 h (38.75 in)

  {{convert|15.1|-|16.3|hand}} → 15.1–16.3 hands (61–67 inches; 155–170 cm)

  {{convert|14.2|to|16.1|hand}} → 14.2 to 16.1 hands (58 to 65 inches; 147 to 165 cm)

Mach (unit of speed)

Conversion of the Mach unit of speed depends on the altitude at which the speed is measured. That altitude should be specified either in feet (for example, |altitude_ft=10,000) or in metres (for example, |altitude_m=3,749). The altitude cannot be determined accurately and only a whole number is accepted.

Examples:

• {{convert|1.6|Mach|altitude_ft=20,000|mph}} → Mach 1.6 (1,130 mph)
• {{convert|1.6|Mach|altitude_m=6,096|mph}} → Mach 1.6 (1,130 mph)
• {{cvt|1130|mph|Mach|altitude_m=6,096|lk=out}} → 1,130 mph (Mach 1.6)
• {{convert|5|-|7|Mach|altitude_ft=34,500}} → Mach 5 – Mach 7 (5,300–7,500 km/h; 3,300–4,600 mph)