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MetroloPy built-in units¶

Units can be referenced by both name and alias. If a unit name or alias contains a space, '*', or '/' character then the name must be enclosed in square brackets, e.g.: '[light year]'. If a unit name or alias contains parentheses and the text inside the parentheses can be interpreted as a Unit then the name must also be enclosed in square brackets. Units can be combined into derived units: spaces or the character '*' represent multiplication, the character '/' represents division and the string '**' represents the power operator. An example of a derived unit reference is 'kg m**2/s' which is equivalent to 'kilogram*metre*metre*second**-1' and to '(kg/s)*m**2'.

Users can also define custom units by creating instances of the Unit class or a sub-class.

The search_units function can list all available units:

In [1]:

from metrolopy import search_units
search_units(fmt='html')

1
acre, 1 acre = 10 ch²
acre-foot, 1 acre ft = 43 560 ft³, aliases: acre-ft, acre ft
ampere (20 prefixes), symbol: A, alias: A
ampere 90 (20 prefixes), 1 A₉₀ = 1 V₉₀/Ω₉₀, alias: A(90)
angstrom, 1 Å = 1 × 10^-10 m, alias: Å
arcminute, 1' = 1/60°, aliases: arcmin, '
arcsecond, 1" = 1/60', aliases: arcsec, "
astronomical unit, 1 au = 1.495 978 707 × 10¹¹ m, aliases: au, ua
bar (20 prefixes), 1 bar = 100 000 Pa
barn, 1 b = 1 × 10^-28 m², alias: b
barrel, 1 bbl = 31.5 gal, aliases: bbl, liquid barrel, liquid-bbl
becquerel (20 prefixes), 1 Bq = 1 1/s, alias: Bq
bel (log base 10, multiplier = 1), 0 B = 1
bit (16 prefixes), symbol: bit, alias: shannon
board-foot, 1 board-foot = 1 ft² in, alias: board-ft
bohr, 1 a₀ = 5.291 772 105 41(80) × 10^-11, aliases: a0, a(0)
bushel, 1 bu = 4 pk, alias: bu
byte (16 prefixes), 1 B = 8 bit, alias: B
cable, 1 cb = 120 ftm, alias: cb
calorie, 1 cal = 4.184 J, aliases: cal, calth, thermochemical calorie
candela (20 prefixes), symbol: cd, alias: cd
chain, 1 ch = 4 rd, alias: ch
coulomb (20 prefixes), 1 C = 1 s A, alias: C
coulomb 90 (20 prefixes), 1 C₉₀ = 1 V₉₀ s/Ω₉₀, alias: C(90)
cubic foot, 1 cu ft = 1 ft³, aliases: cu-ft, cu ft
cubic inch, 1 cu in = 1 in³, aliases: cu-in, cu in
cubic yard, 1 cu yd = 1 yd³, aliases: cu-yd, cu yd
cup, 1 cp = 0.5 pt, alias: cp
dalton (20 prefixes), 1 Da = 1.660 539 068 93(50) × 10^-27, alias: Da
day, 1 d = 24 h, aliases: d, D
decibel (log base 10, multiplier = 10), 0 dB = 1, aliases: dB, dB power, dB-p
decibel femtowatt (log base 10, multiplier = 10), 0 dBf = 1 fW, aliases: dBf, dB(fW)
decibel field (log base 10, multiplier = 20), 0 dB = 1, aliases: dB-f, dB field, dB root-power
decibel hertz (log base 10, multiplier = 10), 0 dB-Hz = 1 Hz, aliases: dB-Hz, dB(Hz)
decibel joule (log base 10, multiplier = 10), 0 dBJ = 1 J, aliases: dBJ, dB(J)
decibel kelvin (log base 10, multiplier = 10), 0 dBK = 1 K, aliases: dBK, dB(K)
decibel kilowatt (log base 10, multiplier = 10), 0 dBk = 1 kW, aliases: dBk, dB(kW)
decibel microvolt (log base 10, multiplier = 20), 0 dBμV = 1 μV, aliases: dBuV, dB(uV), dBμV
decibel microvolt per metre (log base 10, multiplier = 20), 0 dBμ = 1 μV/m, aliases: dBμ, dB(uV/m), decibel microvolt per meter
decibel millivolt (log base 10, multiplier = 20), 0 dBmV = 1 mV, aliases: dBmV, dB(mV)
decibel milliwatt (log base 10, multiplier = 10), 0 dBm = 1 mW, aliases: dBm, dB(mW)
decibel reciprocal kelvin (log base 10, multiplier = 20), 0 dB(K^-1) = 1 1/K, aliases: dB(K**-1), dB(K⁻¹)
decibel reciprocal metre (log base 10, multiplier = 10), 0 dB(m^-1) = 1 1/m, aliases: dB(m**-1), dB(m⁻¹), decibel reciprocal meter
decibel sound intensity level (log base 10, multiplier = 10), 0 dB = 1 × 10^-12 W/m², alias: dB(SIL)
decibel sound power level (log base 10, multiplier = 10), 0 dB = 1 × 10^-12 W, aliases: dB(SWL), dB(pW)
decibel sound pressure level (log base 10, multiplier = 20), 0 dB = 20 μPa, aliases: dB(SPL), dB(20uPa)
decibel square metre (log base 10, multiplier = 10), 0 dBsm = 1 m², aliases: dBsm, dB(m**2), decibel square meter
decibel u (log base 10, multiplier = 20), 0 dBu = 0.774 596 669 241 483 V, alias: dBu
decibel volt (log base 10, multiplier = 20), 0 dBV = 1 V, aliases: dBV, dB(V)
decibel watt (log base 10, multiplier = 10), 0 dBW = 1 W, aliases: dBW, dB(W)
decibel Z (log base 10, multiplier = 10), 0 dBZ = 1 mm⁶/m³, aliases: dBZ, dB(Z)
decibel μPa (log base 10, multiplier = 20), 0 dB = 1 μPa, alias: dB(uPa)
degree, 1° = 0.017 453 292 519 943 3 rad, aliases: deg, °
degree Celsius (non-linear unit), 0 °C = 273.15 K, aliases: degC, deg-C, degree-C, degreeC, °C
degree Fahrenheit (non-linear unit), 0 °F = 459.67 °R, aliases: degF, deg-F, degree-F, degreeF, °F
degree Rankine, 1 °R = 5/9 K, aliases: degR, deg-R, degree-R, degreeR, °R
dram, 1 dr = 0.0625 oz, alias: dr
dry barrel, 1 bu = 7056 in³, alias: dry-bbl
dry gallon, 1 gal = 268.8025 in³, alias: dry-gal
dry pint, 1 pt = 0.5 qt, alias: dry-pt
dry quart, 1 qt = 0.25 gal, alias: dry-qt
dyne (20 prefixes), 1 dyn = 1 × 10^-5 N, alias: dyn
Earth mass, 1 M_⊕ = 5.972 17(13) × 10²⁴ kg, aliases: M(E), M⊕
electon mass, 1 m_e = 9.109 383 714 0(27) × 10^-31, alias: m(e)
electronvolt (20 prefixes), 1 eV = 1.602 176 634 × 10^-19 J, alias: eV
elementary charge, 1 e = 1.602 176 634 × 10^-19 C, alias: e
erg (20 prefixes), 1 erg = 1 × 10^-7 J
farad (20 prefixes), 1 F = 1 C/V, alias: F
farad 90 (20 prefixes), 1 F₉₀ = 1 s/Ω₉₀, alias: F(90)
fathom, 1 ftm = 2 yd, alias: ftm
fluid dram, 1 fl dr = 60 min, aliases: fl-dr, fl dr
fluid ounce, 1 fl oz = 0.25 gi, aliases: fl-oz, fl oz
foot, 1 ft = 12 in, alias: ft
foot-pound, 1 ft·lb = 1 ft lbf, aliases: ft-lb, ft-lbf, ft·lb, ft·lbf
furlong, 1 fur = 10 ch, alias: fur
galileo (20 prefixes), 1 Gal = 1 cm/s², alias: Gal
gallon, 1 gal = 231 in³, aliases: gal, liquid gallon, liquid-gal
gasoline gallon equivalent, 1 gasoline-gallon-equivalent = 33.7 kW h, alias: gasoline-gallon-equivalent
gauss (20 prefixes), 1 G = 1 × 10^-4 T, alias: G
gill, 1 gi = 0.5 cp, alias: gi
grain, 1 gr = 1/7000 lb, alias: gr
gray (20 prefixes), 1 Gy = 1 J/kg, alias: Gy
hand, 1 hand = 4 in
hartley, 1 Hart = 3.321 928 094 887 36 bit, aliases: Hart, ban, dit
hartree, 1 E_h = 1 ℏ²/(m_e a₀²), aliases: E_h, Ha
hectare, 1 ha = 1 hm², alias: ha
henry (20 prefixes), 1 H = 1 Wb/A, alias: H
henry 90 (20 prefixes), 1 H₉₀ = 1 Ω₉₀ s, alias: H(90)
hertz (20 prefixes), 1 Hz = 1 1/s, alias: Hz
hogshead, 1 hogshead = 65 gal
horsepower, 1 hp = 550 lbf ft/s, alias: hp
hour, 1 h = 60 min, alias: h
hundredweight, 1 cwt = 100 lb, alias: cwt
inch (1 prefix), 1 in = 0.0254 m, alias: in
international prototype kilogram, 1 m(𝒦) = 1.000 000 000(12) kg, aliases: m(K), IPK
IT British thermal unit, 1 BTU = 1 055.055 852 62 J, aliases: BTU, Btu
jansky, 1 Jy = 1 × 10^-26 W/(Hz m²), alias: Jy
joule (20 prefixes), 1 J = 1 N m, alias: J
Julian year (4 prefixes), 1 a = 365.25 d, aliases: a, annum, year, yr
Jupiter mass, 1 M_J = 1.898 518(43) × 10²⁷ kg, aliases: M(J), M(Jup)
katal (20 prefixes), 1 kat = 1 mol/s, alias: kat
kelvin (20 prefixes), symbol: K, alias: K
kelvin 54 (20 prefixes), 1 K₅₄ = 1.000 000 00(37), alias: K(54)
kilogram (20 prefixes), symbol: kg, alias: kg
knot, 1 kn = 1 M/h, alias: kn
large calorie, 1 Cal = 1000 cal, aliases: Cal, Calorie, dietary calorie, kcal, kilocalorie
league, 1 lea = 3 mi, alias: lea
light hour, 1 light-hour = 1 c h, alias: light-hour
light minute, 1 light-minute = 1 c min, alias: light-minute
light second, 1 light-second = 1 c s, alias: light-second
light year, 1 ly = 1 c a, alias: ly
link, 1 li = 0.66 ft, alias: li
litre (20 prefixes), 1 L = 1 dm³, aliases: L, liter
long hundredweight, 1 long cwt = 112 lb, alias: long cwt
long ton, 1 long ton = 2240 lb
lumen (20 prefixes), 1 lm = 1 sr cd, alias: lm
lux (20 prefixes), 1 lx = 1 lm/m², alias: lx
maxwell (20 prefixes), 1 Mx = 1 × 10^-8 Wb, alias: Mx
metre (20 prefixes), symbol: m, aliases: m, meter
mile, 1 mi = 1760 yd, alias: mi
millibel milliwatt (log base 10, multiplier = 1000), 0 mBm = 1 mW, aliases: mBm, mB(mW)
millimetre of mercury, 1 mmHg = 133.322 387 415 Pa, alias: mmHg
minim, 1 min = 0.125 tsp
minute, 1 min = 60 s, alias: min
mole (20 prefixes), symbol: mol, alias: mol
moment magnitude (log base 10, multiplier = 2/3), -10.7 M_W = 1 dyn cm, aliases: M(W), MMS
monochromatic AB magnitude (log base 10, multiplier = -2.5), 0 m_AB = 3631 Jy, alias: m(AB)
natural unit of action, 1 ℏ = 1.054 571 817 646 156 472(49) × 10^-34 J s, aliases: h-bar, ℏ
natural unit of information, 1 nat = 1.442 695 040 888 96 bit, aliases: nat, nepit, nit
nautical mile, 1 M = 1852 m, aliases: M, Nm, NM, nmi
neper (log base e, multiplier = 1), 0 Np = 1, alias: Np
newton (20 prefixes), 1 N = 1 m kg/s², alias: N
nibble, 1 nibble = 4 bit, aliases: nybble, nyble
oersted (20 prefixes), 1 Oe = 79.577 471 545 947 673 8(37) A/m, alias: Oe
ohm (20 prefixes), 1 Ω = 1 V/A, aliases: Ohm, Ω
ohm 90 (20 prefixes), 1 Ω₉₀ = 1.000 000 017 793 667 564 3... Ω, aliases: ohm(90), Ω(90)
oil barrel, 1 bbl = 42 gal
ounce, 1 oz = 0.0625 lb, aliases: oz, avdp-oz, avoirdupois ounce
parsec (3 prefixes), 1 pc = 206 264.806 247 096 363 2(97) au, alias: pc
part per billion, 1 ppb = 1 × 10^-9, alias: ppb
part per million, 1 ppm = 1 × 10^-6, alias: ppm
part per quadrillion, 1 ppq = 1 × 10^-15, alias: ppq
part per trillion, 1 ppt = 1 × 10^-12, alias: ppt
pascal (20 prefixes), 1 Pa = 1 N/m², alias: Pa
peck, 1 pk = 2 gal, alias: pk
pennyweight, 1 dwt = 24 gr, alias: dwt
percent, 1% = 0.01, alias: %
phot (20 prefixes), 1 ph = 1 sr cd/cm², alias: ph
pica, 1 P/ = 1/6 in, alias: P/
pint, 1 pt = 0.5 qt, aliases: pt, liquid pint, liquid-pt
Planck charge, 1 q_P = 1.875 546 038 42(14) × 10^-18, alias: q(P)
Planck length, 1 l_P = 1.616 255(18) × 10^-35 m, alias: l(P)
Planck mass, 1 m_P = 1.257 000(14) × 10^-12 c^1/2, alias: m(P)
Planck temperature, 1 T_P = 1.416 784(16) × 10³² K, alias: T(P)
Planck time, 1 t_P = 5.391 246(61) × 10^-44 s, alias: t(P)
point, 1 p = 1/12 P/, alias: p
poise (20 prefixes), 1 P = 1 dyn s/cm², alias: P
pound (1 prefix), 1 lb = 0.453 592 37 kg, aliases: lb, avdp-lb, avoirdupois pound, lbm, pound mass
pound force, 1 lbf = 9.806 65 lb m/s², alias: lbf
pound per square inch, 1 psi = 1 lbf/in², alias: psi
pound-foot, 1 lb·ft = 1 ft lbf, aliases: lb-ft, lbf-lft, lbf·ft, lb·ft
proton mass, 1 m_p = 1.672 621 925 97(50) × 10^-27, alias: m(p)
quart, 1 qt = 0.25 gal, aliases: qt, liquid quart, liquid-qt
rack unit, 1 U = 1.75 in
radian (20 prefixes), 1 rad = 1 m/m, alias: rad
reduced Compton wavelength, 1 ƛ_C = 1 ℏ/(m_e c), aliases: lambda(C), ƛ(C)
rod, 1 rd = 25 ft, alias: rd
root hertz, 1 √Hz = 1 Hz^1/2, aliases: sqrtHz, √Hz
second (20 prefixes), symbol: s, alias: s
section, 1 section = 640 acre
short ton, 1 tn = 2000 lb, alias: tn
shot, 1 jig = 3 Tbsp, alias: jig
siemens (20 prefixes), 1 S = 1 A/V, aliases: S, mho
sievert (20 prefixes), 1 Sv = 1 J/kg, alias: Sv
siriometer, 1 Sm = 1 000 000 au
slug, 1 slug = 1 lbf s²/ft
solar mass, 1 M_☉ = 1.988 410(45) × 10³⁰ kg, aliases: M(solar), M(Sun), M☉
speed of light, 1 c = 2.997 924 58 × 10⁸ m/s, alias: c
square, 1 square = 100 ft²
standard atmosphere, 1 atm = 101 325 Pa, alias: atm
steradian (20 prefixes), 1 sr = 1 m²/m², alias: sr
stilb (20 prefixes), 1 sb = 1 cd/cm², alias: sb
stokes (20 prefixes), 1 St = 1 cm²/s, alias: St
survey foot, 1 ft = 1200/3937 m
survey mile, 1 mi = 8 fur, alias: statute mile
survey township, 1 twp = 36 section, alias: twp
tablespoon, 1 Tbsp = 0.5 fl oz, alias: Tbsp
teaspoon, 1 tsp = 1/3 Tbsp, alias: tsp
tesla (20 prefixes), 1 T = 1 Wb/m², alias: T
thousandth of an inch, 1 mil = 0.001 in, aliases: mil, thou, thousandth
tonne (12 prefixes), 1 t = 1000 kg, aliases: t, metric ton, metric-ton
tons of TNT equivalent (3 prefixes), 1 t(TNT) = 4.184 GJ, aliases: t(TNT), tons of tnt, tons of TNT
torr (1 prefix), 1 Torr = 20265/152 Pa, alias: Torr
troy ounce, 1 oz t = 20 dwt, aliases: oz-t, oz t
troy pound, 1 lb t = 12 oz t, aliases: lb-t, lb t
volt (20 prefixes), 1 V = 1 W/A, alias: V
volt 90 (20 prefixes), 1 V₉₀ = 1.000 000 106 665 107 250 6... V, alias: V(90)
volt ampere (20 prefixes), 1 VA = 1 V A, alias: VA
volt ampere reactive (20 prefixes), 1 var = 1 V A, alias: var
watt (20 prefixes), 1 W = 1 J/s, alias: W
watt 90 (20 prefixes), 1 W₉₀ = 1 V₉₀ A₉₀, alias: W(90)
wavenumber, alias for: 1/cm
weber (20 prefixes), 1 Wb = 1 V s, alias: Wb
yard, 1 yd = 3 ft, alias: yd