Unit conversions

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The code related to this tool is now a part of Opasnet (R library) (function convert.units).

Convert almost any unit to any other unit!

What is the amount?: In what units is it?: To what units do you want it? (blank: basic SI units):

Question

How to convert data from one unit to another in R?

Answer

We need conversion factors, which are listed below, and a code that does the actual conversion. Function convert.units is used to perform conversions. It has three parameters:

• x: a numeric vector of values that are to be converted.
• tounit: a character vector of units that are preferred in the output. This can contain more units than needed, as long as the the entries are exclusive (i.e., only one unit for length, only one for energy etc.).
• fromunit: a character vector of units used in the input. It has (or is coerced to) the same size as x.

Composite units can be used, e.g. ug /m3. Then, each part of the unit is converted separately, e.g. micrograms to picograms and cubic metre to litres.

> convert.units(1, tounit = c("pg", "l"), fromunit = "ug /m3")

will result in

Unit	Result
pg /l	1000

Note that in the units, different parts are separated with space, but the units in the denominator must have the slash before them without a space.

Unit conversions(-)

Obs	From	To	Type	Result	Description
1			Prefix	1	basic unit
2	da		Prefix	10	deca
3	h		Prefix	100	hecto
4	k		Prefix	1000	kilo
5	M		Prefix	1e+6	mega
6	G		Prefix	1e+9	giga
7	T		Prefix	1e+12	tera
8	P		Prefix	1e+15	peta
9	E		Prefix	1e+18	exa
10	Z		Prefix	1e+21	zetta
11	Y		Prefix	1e+24	yotta
12	d		Prefix	0.1	deci
13	c		Prefix	0.01	centi
14	m		Prefix	0.001	milli
15	μ		Prefix	1e-6	micro
16	u		Prefix	1e-6	micro
17	n		Prefix	1e-9	nano
18	p		Prefix	1e-12	pico
19	f		Prefix	1e-15	femto
20	a		Prefix	1e-18	atto
21	z		Prefix	1e-21	zepto
22	y		Prefix	1e-24	yocto
23	J	J	Unit	1	Joule, the Si unit of energy
24	Wh	J	Unit	3600	1 Wh = 1 Wh * 3600 s/h = 3600 Ws = 3600 MJ
25	toe	J	Unit	3.5e+10	1 toe = 1000 kgoe = 1000 kg * 35 MJ/kg = 35000 MJ (energy as tons of oil equivalent)
26	cal	J	Unit	4.1868	calorie
27	eV	J	Unit	1.602176565e-19	electronvolt
28	g	g	Unit	1	gram, the SI unit of mass (although the definition is based on kg)
29	ton	g	Unit	1e+6	metric ton
30	tn	g	Unit	1e+6	metric ton
31	lb	g	Unit	453.59237	international avoirdupois pound
32	s	s	Unit	1	second, the SI unit of time
33	min	s	Unit	60	minute
34	h	s	Unit	3600	hour
35	d	s	Unit	86400	day
36	a	s	Unit	31557600	year (assuming 365.25 days per year)
37	m	m	Unit	1	metre, the SI unit of length
38	in	m	Unit	0.0254	inch (strangely, some people still use these)
39	ft	m	Unit	0.3048	foot = 12 inches
40	mi	m	Unit	1609.344	mile = 5280 feet
41	Å	m	Unit	1e-10	1 angstrom = 100 pm
42	m3	m3	Unit	1	cubic metre, the SI unit of volume
43	l	m3	Unit	0.001	litre
44	m^3	m3	Unit	1
45	A	A	Unit	1	Ampere, the SI unit of electric current
46	V	V	Unit	1	Volt, the SI unit of electric potential
47	N	N	Unit	1	Newton, the SI unit of force
48	W	W	Unit	1	Watt, the SI unit of power
49	hp	W	Unit	735.498 75	horsepower (metric)
50	Pa	Pa	Unit	1	Pascal, the SI unit of pressure
51	psi	Pa	Unit	6894.757	pound-force per square inch
52	bar	Pa	Unit	100000	bar
53	atm	Pa	Unit	101325	atmosphere (standard)
54	mol	mol	Unit	1	mole, the SI unit of substance amount
55	M	mol /l	Unit	1
56	Hz	Hz	Unit	1	Hertz, the SI unit of frequency
57	Hz	/s	Unit	1
58	C	C	Unit	1	Coulomb, the SI unit of electric quantity
59	O	O	Unit	1	Ohm, the SI unit of resistance
60	F	F	Unit	1	Farad, the SI unit of capacitance
61	Wb	Wb	Unit	1	Weber, the SI unit of magnetic flux
62	-	%	Unit	0.01	Fraction

Rationale

Help

Start out by filling in the amount in the first field. In the second field write the original units from which you wish to convert. The third field is for the units you wish to convert the amount to. If you leave this blank, the amount will be converted to basic SI units.

There are several things to notify when filling the second and third fields:

• Mark the units between apostrophies.
• Leave a space between different units.
• Do not leave a space after a division slash.

Press Run code to execute the conversion tool. Wait a moment for it to complete the conversion.

See also

• An R package for converting units

Related files

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