Constants (scipy.constants)#

Physical and mathematical constants and units.

Mathematical constants#

pi

Pi

golden

Golden ratio

golden_ratio

Golden ratio

Physical constants#

The following physical constants are available as attributes of scipy.constants. All units are SI.

Attribute

Quantity

Units

c

speed of light in vacuum

m s^-1

speed_of_light

speed of light in vacuum

m s^-1

mu_0

the magnetic constant \(\mu_0\)

N A^-2

epsilon_0

the electric constant (vacuum permittivity), \(\epsilon_0\)

F m^-1

h

the Planck constant \(h\)

J Hz^-1

Planck

the Planck constant \(h\)

J Hz^-1

hbar

the reduced Planck constant, \(\hbar = h/(2\pi)\)

J s

G

Newtonian constant of gravitation

m^3 kg^-1 s^-2

gravitational_constant

Newtonian constant of gravitation

m^3 kg^-1 s^-2

g

standard acceleration of gravity

m s^-2

e

elementary charge

C

elementary_charge

elementary charge

C

R

molar gas constant

J mol^-1 K^-1

gas_constant

molar gas constant

J mol^-1 K^-1

alpha

fine-structure constant

(unitless)

fine_structure

fine-structure constant

(unitless)

N_A

Avogadro constant

mol^-1

Avogadro

Avogadro constant

mol^-1

k

Boltzmann constant

J K^-1

Boltzmann

Boltzmann constant

J K^-1

sigma

Stefan-Boltzmann constant \(\sigma\)

W m^-2 K^-4

Stefan_Boltzmann

Stefan-Boltzmann constant \(\sigma\)

W m^-2 K^-4

Wien

Wien wavelength displacement law constant

m K

Rydberg

Rydberg constant

m^-1

m_e

electron mass

kg

electron_mass

electron mass

kg

m_p

proton mass

kg

proton_mass

proton mass

kg

m_n

neutron mass

kg

neutron_mass

neutron mass

kg

Constants database#

In addition to the above variables, scipy.constants also contains the 2022 CODATA recommended values [CODATA2022] database containing more physical constants.

value(key)

Value in physical_constants indexed by key

unit(key)

Unit in physical_constants indexed by key

precision(key)

Relative precision in physical_constants indexed by key

find([sub, disp])

Return list of physical_constant keys containing a given string.

ConstantWarning

Accessing a constant no longer in current CODATA data set

scipy.constants.physical_constants#

Dictionary of physical constants, of the format physical_constants[name] = (value, unit, uncertainty). The CODATA database uses ellipses to indicate that a value is defined (exactly) in terms of others but cannot be represented exactly with the allocated number of digits. In these cases, SciPy calculates the derived value and reports it to the full precision of a Python float. Although physical_constants lists the uncertainty as 0.0 to indicate that the CODATA value is exact, the value in physical_constants is still subject to the truncation error inherent in double-precision representation.

Available constants:

alpha particle mass

6.644657345e-27 kg

alpha particle mass energy equivalent

5.9719201997e-10 J

alpha particle mass energy equivalent in MeV

3727.3794118 MeV

alpha particle mass in u

4.001506179129 u

alpha particle molar mass

0.0040015061833 kg mol^-1

alpha particle relative atomic mass

4.001506179129

alpha particle rms charge radius

1.6785e-15 m

alpha particle-electron mass ratio

7294.29954171

alpha particle-proton mass ratio

3.972599690252

Angstrom star

1.00001495e-10 m

atomic mass constant

1.66053906892e-27 kg

atomic mass constant energy equivalent

1.49241808768e-10 J

atomic mass constant energy equivalent in MeV

931.49410372 MeV

atomic mass unit-electron volt relationship

931494103.72 eV

atomic mass unit-hartree relationship

34231776.922 E_h

atomic mass unit-hertz relationship

2.25234272185e+23 Hz

atomic mass unit-inverse meter relationship

751300662090000.0 m^-1

atomic mass unit-joule relationship

1.49241808768e-10 J

atomic mass unit-kelvin relationship

10809540206700.0 K

atomic mass unit-kilogram relationship

1.66053906892e-27 kg

atomic unit of 1st hyperpolarizability

3.2063612996e-53 C^3 m^3 J^-2

atomic unit of 2nd hyperpolarizability

6.2353799735e-65 C^4 m^4 J^-3

atomic unit of action

1.0545718176461565e-34 J s

atomic unit of charge

1.602176634e-19 C

atomic unit of charge density

1081202386770.0 C m^-3

atomic unit of current

0.0066236182375082 A

atomic unit of electric dipole mom.

8.4783536198e-30 C m

atomic unit of electric field

514220675112.0 V m^-1

atomic unit of electric field gradient

9.7173624424e+21 V m^-2

atomic unit of electric polarizability

1.64877727212e-41 C^2 m^2 J^-1

atomic unit of electric potential

27.211386245981 V

atomic unit of electric quadrupole mom.

4.4865515185e-40 C m^2

atomic unit of energy

4.359744722206e-18 J

atomic unit of force

8.2387235038e-08 N

atomic unit of length

5.29177210544e-11 m

atomic unit of mag. dipole mom.

1.85480201315e-23 J T^-1

atomic unit of mag. flux density

235051.757077 T

atomic unit of magnetizability

7.8910365794e-29 J T^-2

atomic unit of mass

9.1093837139e-31 kg

atomic unit of momentum

1.99285191545e-24 kg m s^-1

atomic unit of permittivity

1.1126500562e-10 F m^-1

atomic unit of time

2.4188843265864e-17 s

atomic unit of velocity

2187691.26216 m s^-1

Avogadro constant

6.02214076e+23 mol^-1

Bohr magneton

9.2740100657e-24 J T^-1

Bohr magneton in eV/T

5.7883817982e-05 eV T^-1

Bohr magneton in Hz/T

13996244917.1 Hz T^-1

Bohr magneton in inverse meter per tesla

46.686447719 m^-1 T^-1

Bohr magneton in K/T

0.67171381472 K T^-1

Bohr radius

5.29177210544e-11 m

Boltzmann constant

1.380649e-23 J K^-1

Boltzmann constant in eV/K

8.617333262145179e-05 eV K^-1

Boltzmann constant in Hz/K

20836619123.327576 Hz K^-1

Boltzmann constant in inverse meter per kelvin

69.50348004861274 m^-1 K^-1

characteristic impedance of vacuum

376.730313412 ohm

classical electron radius

2.8179403205e-15 m

Compton wavelength

2.42631023538e-12 m

conductance quantum

7.748091729863649e-05 S

conventional value of ampere-90

1.0000000888714378 A

conventional value of coulomb-90

1.0000000888714378 C

conventional value of farad-90

0.9999999822063325 F

conventional value of henry-90

1.0000000177936679 H

conventional value of Josephson constant

483597900000000.0 Hz V^-1

conventional value of ohm-90

1.0000000177936679 ohm

conventional value of volt-90

1.0000001066651072 V

conventional value of von Klitzing constant

25812.807 ohm

conventional value of watt-90

1.0000001955365543 W

Copper x unit

1.00207697e-13 m

deuteron g factor

0.8574382335

deuteron mag. mom.

4.330735087e-27 J T^-1

deuteron mag. mom. to Bohr magneton ratio

0.0004669754568

deuteron mag. mom. to nuclear magneton ratio

0.8574382335

deuteron mass

3.3435837768e-27 kg

deuteron mass energy equivalent

3.00506323491e-10 J

deuteron mass energy equivalent in MeV

1875.612945 MeV

deuteron mass in u

2.013553212544 u

deuteron molar mass

0.00201355321466 kg mol^-1

deuteron relative atomic mass

2.013553212544

deuteron rms charge radius

2.12778e-15 m

deuteron-electron mag. mom. ratio

-0.000466434555

deuteron-electron mass ratio

3670.482967655

deuteron-neutron mag. mom. ratio

-0.44820652

deuteron-proton mag. mom. ratio

0.3070122093

deuteron-proton mass ratio

1.9990075012699

electron charge to mass quotient

-175882000838.0 C kg^-1

electron g factor

-2.00231930436092

electron gyromag. ratio

176085962784.0 s^-1 T^-1

electron gyromag. ratio in MHz/T

28024.9513861 MHz T^-1

electron mag. mom.

-9.2847646917e-24 J T^-1

electron mag. mom. anomaly

0.00115965218046

electron mag. mom. to Bohr magneton ratio

-1.00115965218046

electron mag. mom. to nuclear magneton ratio

-1838.281971877

electron mass

9.1093837139e-31 kg

electron mass energy equivalent

8.187105788e-14 J

electron mass energy equivalent in MeV

0.51099895069 MeV

electron mass in u

0.0005485799090441 u

electron molar mass

5.4857990962e-07 kg mol^-1

electron relative atomic mass

0.0005485799090441

electron to alpha particle mass ratio

0.0001370933554733

electron to shielded helion mag. mom. ratio

864.05823986

electron to shielded proton mag. mom. ratio

-658.2275856

electron volt

1.602176634e-19 J

electron volt-atomic mass unit relationship

1.07354410083e-09 u

electron volt-hartree relationship

0.036749322175665 E_h

electron volt-hertz relationship

241798924208491.8 Hz

electron volt-inverse meter relationship

806554.3937349211 m^-1

electron volt-joule relationship

1.602176634e-19 J

electron volt-kelvin relationship

11604.518121550082 K

electron volt-kilogram relationship

1.7826619216278975e-36 kg

electron-deuteron mag. mom. ratio

-2143.9234921

electron-deuteron mass ratio

0.0002724437107629

electron-helion mass ratio

0.0001819543074649

electron-muon mag. mom. ratio

206.7669881

electron-muon mass ratio

0.0048363317

electron-neutron mag. mom. ratio

960.92048

electron-neutron mass ratio

0.00054386734416

electron-proton mag. mom. ratio

-658.21068789

electron-proton mass ratio

0.0005446170214889

electron-tau mass ratio

0.000287585

electron-triton mass ratio

0.0001819200062327

elementary charge

1.602176634e-19 C

elementary charge over h-bar

1519267447878626.0 A J^-1

Faraday constant

96485.33212331001 C mol^-1

Fermi coupling constant

1.1663787e-05 GeV^-2

fine-structure constant

0.0072973525643

first radiation constant

3.7417718521927573e-16 W m^2

first radiation constant for spectral radiance

1.1910429723971884e-16 W m^2 sr^-1

Hartree energy

4.359744722206e-18 J

Hartree energy in eV

27.211386245981 eV

hartree-atomic mass unit relationship

2.92126231797e-08 u

hartree-electron volt relationship

27.211386245981 eV

hartree-hertz relationship

6579683920499900.0 Hz

hartree-inverse meter relationship

21947463.136314 m^-1

hartree-joule relationship

4.359744722206e-18 J

hartree-kelvin relationship

315775.02480398 K

hartree-kilogram relationship

4.8508702095419e-35 kg

helion g factor

-4.2552506995

helion mag. mom.

-1.07461755198e-26 J T^-1

helion mag. mom. to Bohr magneton ratio

-0.00115874098083

helion mag. mom. to nuclear magneton ratio

-2.1276253498

helion mass

5.0064127862e-27 kg

helion mass energy equivalent

4.4995394185e-10 J

helion mass energy equivalent in MeV

2808.39161112 MeV

helion mass in u

3.014932246932 u

helion molar mass

0.0030149322501 kg mol^-1

helion relative atomic mass

3.014932246932

helion shielding shift

5.9967029e-05

helion-electron mass ratio

5495.88527984

helion-proton mass ratio

2.993152671552

hertz-atomic mass unit relationship

4.439821659e-24 u

hertz-electron volt relationship

4.135667696923859e-15 eV

hertz-hartree relationship

1.5198298460574e-16 E_h

hertz-inverse meter relationship

3.3356409519815204e-09 m^-1

hertz-joule relationship

6.62607015e-34 J

hertz-kelvin relationship

4.799243073366221e-11 K

hertz-kilogram relationship

7.372497323812708e-51 kg

hyperfine transition frequency of Cs-133

9192631770.0 Hz

inverse fine-structure constant

137.035999177

inverse meter-atomic mass unit relationship

1.33102504824e-15 u

inverse meter-electron volt relationship

1.2398419843320026e-06 eV

inverse meter-hartree relationship

4.5563352529132e-08 E_h

inverse meter-hertz relationship

299792458.0 Hz

inverse meter-joule relationship

1.9864458571489286e-25 J

inverse meter-kelvin relationship

0.014387768775039337 K

inverse meter-kilogram relationship

2.2102190943042335e-42 kg

inverse of conductance quantum

12906.403729652257 ohm

Josephson constant

483597848416983.6 Hz V^-1

joule-atomic mass unit relationship

6700535247.1 u

joule-electron volt relationship

6.241509074460763e+18 eV

joule-hartree relationship

2.2937122783969e+17 E_h

joule-hertz relationship

1.5091901796421518e+33 Hz

joule-inverse meter relationship

5.03411656754271e+24 m^-1

joule-kelvin relationship

7.24297051603992e+22 K

joule-kilogram relationship

1.1126500560536185e-17 kg

kelvin-atomic mass unit relationship

9.2510872884e-14 u

kelvin-electron volt relationship

8.617333262145179e-05 eV

kelvin-hartree relationship

3.1668115634564e-06 E_h

kelvin-hertz relationship

20836619123.327576 Hz

kelvin-inverse meter relationship

69.50348004861274 m^-1

kelvin-joule relationship

1.380649e-23 J

kelvin-kilogram relationship

1.5361791872403723e-40 kg

kilogram-atomic mass unit relationship

6.0221407537e+26 u

kilogram-electron volt relationship

5.609588603804452e+35 eV

kilogram-hartree relationship

2.0614857887415e+34 E_h

kilogram-hertz relationship

1.3563924896521321e+50 Hz

kilogram-inverse meter relationship

4.524438335443823e+41 m^-1

kilogram-joule relationship

8.987551787368176e+16 J

kilogram-kelvin relationship

6.509657260728958e+39 K

lattice parameter of silicon

5.431020511e-10 m

lattice spacing of ideal Si (220)

1.920155716e-10 m

Loschmidt constant (273.15 K, 100 kPa)

2.6516458048837345e+25 m^-3

Loschmidt constant (273.15 K, 101.325 kPa)

2.686780111798444e+25 m^-3

luminous efficacy

683.0 lm W^-1

mag. flux quantum

2.0678338484619295e-15 Wb

molar gas constant

8.31446261815324 J mol^-1 K^-1

molar mass constant

0.00100000000105 kg mol^-1

molar mass of carbon-12

0.0120000000126 kg mol^-1

molar Planck constant

3.990312712893431e-10 J Hz^-1 mol^-1

molar volume of ideal gas (273.15 K, 100 kPa)

0.02271095464148557 m^3 mol^-1

molar volume of ideal gas (273.15 K, 101.325 kPa)

0.022413969545014137 m^3 mol^-1

molar volume of silicon

1.205883199e-05 m^3 mol^-1

Molybdenum x unit

1.00209952e-13 m

muon Compton wavelength

1.17344411e-14 m

muon g factor

-2.00233184123

muon mag. mom.

-4.4904483e-26 J T^-1

muon mag. mom. anomaly

0.00116592062

muon mag. mom. to Bohr magneton ratio

-0.00484197048

muon mag. mom. to nuclear magneton ratio

-8.89059704

muon mass

1.883531627e-28 kg

muon mass energy equivalent

1.692833804e-11 J

muon mass energy equivalent in MeV

105.6583755 MeV

muon mass in u

0.1134289257 u

muon molar mass

0.0001134289258 kg mol^-1

muon-electron mass ratio

206.7682827

muon-neutron mass ratio

0.1124545168

muon-proton mag. mom. ratio

-3.183345146

muon-proton mass ratio

0.1126095262

muon-tau mass ratio

0.0594635

natural unit of action

1.0545718176461565e-34 J s

natural unit of action in eV s

6.582119569509067e-16 eV s

natural unit of energy

8.187105788e-14 J

natural unit of energy in MeV

0.51099895069 MeV

natural unit of length

3.8615926744e-13 m

natural unit of mass

9.1093837139e-31 kg

natural unit of momentum

2.730924488e-22 kg m s^-1

natural unit of momentum in MeV/c

0.5109989461 MeV/c

natural unit of time

1.28808866644e-21 s

natural unit of velocity

299792458.0 m s^-1

neutron Compton wavelength

1.31959090382e-15 m

neutron g factor

-3.82608552

neutron gyromag. ratio

183247174.0 s^-1 T^-1

neutron gyromag. ratio in MHz/T

29.1646935 MHz T^-1

neutron mag. mom.

-9.6623653e-27 J T^-1

neutron mag. mom. to Bohr magneton ratio

-0.00104187565

neutron mag. mom. to nuclear magneton ratio

-1.91304276

neutron mass

1.67492750056e-27 kg

neutron mass energy equivalent

1.50534976514e-10 J

neutron mass energy equivalent in MeV

939.56542194 MeV

neutron mass in u

1.00866491606 u

neutron molar mass

0.00100866491712 kg mol^-1

neutron relative atomic mass

1.00866491606

neutron to shielded proton mag. mom. ratio

-0.68499694

neutron-electron mag. mom. ratio

0.00104066884

neutron-electron mass ratio

1838.683662

neutron-muon mass ratio

8.89248408

neutron-proton mag. mom. ratio

-0.68497935

neutron-proton mass difference

2.30557461e-30 kg

neutron-proton mass difference energy equivalent

2.07214712e-13 J

neutron-proton mass difference energy equivalent in MeV

1.29333251 MeV

neutron-proton mass difference in u

0.00138844948 u

neutron-proton mass ratio

1.00137841946

neutron-tau mass ratio

0.528779

Newtonian constant of gravitation

6.6743e-11 m^3 kg^-1 s^-2

Newtonian constant of gravitation over h-bar c

6.70883e-39 (GeV/c^2)^-2

nuclear magneton

5.0507837393e-27 J T^-1

nuclear magneton in eV/T

3.15245125417e-08 eV T^-1

nuclear magneton in inverse meter per tesla

0.0254262341009 m^-1 T^-1

nuclear magneton in K/T

0.00036582677706 K T^-1

nuclear magneton in MHz/T

7.6225932188 MHz T^-1

Planck constant

6.62607015e-34 J Hz^-1

Planck constant in eV/Hz

4.135667696923859e-15 eV Hz^-1

Planck length

1.616255e-35 m

Planck mass

2.176434e-08 kg

Planck mass energy equivalent in GeV

1.22089e+19 GeV

Planck temperature

1.416784e+32 K

Planck time

5.391247e-44 s

proton charge to mass quotient

95788331.43 C kg^-1

proton Compton wavelength

1.3214098536e-15 m

proton g factor

5.5856946893

proton gyromag. ratio

267522187.08 s^-1 T^-1

proton gyromag. ratio in MHz/T

42.577478461 MHz T^-1

proton mag. mom.

1.41060679545e-26 J T^-1

proton mag. mom. to Bohr magneton ratio

0.0015210322023

proton mag. mom. to nuclear magneton ratio

2.79284734463

proton mag. shielding correction

2.56715e-05

proton mass

1.67262192595e-27 kg

proton mass energy equivalent

1.50327761802e-10 J

proton mass energy equivalent in MeV

938.27208943 MeV

proton mass in u

1.0072764665789 u

proton molar mass

0.00100727646764 kg mol^-1

proton relative atomic mass

1.0072764665789

proton rms charge radius

8.4075e-16 m

proton-electron mass ratio

1836.152673426

proton-muon mass ratio

8.88024338

proton-neutron mag. mom. ratio

-1.45989802

proton-neutron mass ratio

0.99862347797

proton-tau mass ratio

0.528051

quantum of circulation

0.00036369475467 m^2 s^-1

quantum of circulation times 2

0.00072738950934 m^2 s^-1

reduced Compton wavelength

3.8615926744e-13 m

reduced muon Compton wavelength

1.867594306e-15 m

reduced neutron Compton wavelength

2.100194152e-16 m

reduced Planck constant

1.0545718176461565e-34 J s

reduced Planck constant in eV s

6.582119569509067e-16 eV s

reduced Planck constant times c in MeV fm

197.3269804593025 MeV fm

reduced proton Compton wavelength

2.10308910051e-16 m

reduced tau Compton wavelength

1.110538e-16 m

Rydberg constant

10973731.568157 m^-1

Rydberg constant times c in Hz

3289841960250000.0 Hz

Rydberg constant times hc in eV

13.60569312299 eV

Rydberg constant times hc in J

2.179872361103e-18 J

Sackur-Tetrode constant (1 K, 100 kPa)

-1.15170753496

Sackur-Tetrode constant (1 K, 101.325 kPa)

-1.16487052149

second radiation constant

0.014387768775039337 m K

shielded helion gyromag. ratio

203789460.78 s^-1 T^-1

shielded helion gyromag. ratio in MHz/T

32.434100033 MHz T^-1

shielded helion mag. mom.

-1.07455311035e-26 J T^-1

shielded helion mag. mom. to Bohr magneton ratio

-0.00115867149457

shielded helion mag. mom. to nuclear magneton ratio

-2.1274977624

shielded helion to proton mag. mom. ratio

-0.76176657721

shielded helion to shielded proton mag. mom. ratio

-0.7617861334

shielded proton gyromag. ratio

267515319.4 s^-1 T^-1

shielded proton gyromag. ratio in MHz/T

42.57638543 MHz T^-1

shielded proton mag. mom.

1.410570583e-26 J T^-1

shielded proton mag. mom. to Bohr magneton ratio

0.0015209931551

shielded proton mag. mom. to nuclear magneton ratio

2.792775648

shielding difference of d and p in HD

1.9877e-08

shielding difference of t and p in HT

2.3945e-08

speed of light in vacuum

299792458.0 m s^-1

standard acceleration of gravity

9.80665 m s^-2

standard atmosphere

101325.0 Pa

standard-state pressure

100000.0 Pa

Stefan-Boltzmann constant

5.6703744191844314e-08 W m^-2 K^-4

tau Compton wavelength

6.97771e-16 m

tau energy equivalent

1776.86 MeV

tau mass

3.16754e-27 kg

tau mass energy equivalent

2.84684e-10 J

tau mass in u

1.90754 u

tau molar mass

0.00190754 kg mol^-1

tau-electron mass ratio

3477.23

tau-muon mass ratio

16.817

tau-neutron mass ratio

1.89115

tau-proton mass ratio

1.89376

Thomson cross section

6.6524587051e-29 m^2

triton g factor

5.95792493

triton mag. mom.

1.5046095178e-26 J T^-1

triton mag. mom. to Bohr magneton ratio

0.0016223936648

triton mag. mom. to nuclear magneton ratio

2.978962465

triton mass

5.0073567512e-27 kg

triton mass energy equivalent

4.5003878119e-10 J

triton mass energy equivalent in MeV

2808.92113668 MeV

triton mass in u

3.01550071597 u

triton molar mass

0.00301550071913 kg mol^-1

triton relative atomic mass

3.01550071597

triton to proton mag. mom. ratio

1.0666399189

triton-electron mass ratio

5496.92153551

triton-proton mass ratio

2.99371703403

unified atomic mass unit

1.66053906892e-27 kg

vacuum electric permittivity

8.8541878188e-12 F m^-1

vacuum mag. permeability

1.25663706127e-06 N A^-2

von Klitzing constant

25812.807459304513 ohm

W to Z mass ratio

0.88145

weak mixing angle

0.22305

Wien frequency displacement law constant

58789257576.468254 Hz K^-1

Wien wavelength displacement law constant

0.0028977719551851727 m K

Units#

SI prefixes#

quetta

\(10^{30}\)

ronna

\(10^{27}\)

yotta

\(10^{24}\)

zetta

\(10^{21}\)

exa

\(10^{18}\)

peta

\(10^{15}\)

tera

\(10^{12}\)

giga

\(10^{9}\)

mega

\(10^{6}\)

kilo

\(10^{3}\)

hecto

\(10^{2}\)

deka

\(10^{1}\)

deci

\(10^{-1}\)

centi

\(10^{-2}\)

milli

\(10^{-3}\)

micro

\(10^{-6}\)

nano

\(10^{-9}\)

pico

\(10^{-12}\)

femto

\(10^{-15}\)

atto

\(10^{-18}\)

zepto

\(10^{-21}\)

yocto

\(10^{-24}\)

ronto

\(10^{-27}\)

quecto

\(10^{-30}\)

Binary prefixes#

kibi

\(2^{10}\)

mebi

\(2^{20}\)

gibi

\(2^{30}\)

tebi

\(2^{40}\)

pebi

\(2^{50}\)

exbi

\(2^{60}\)

zebi

\(2^{70}\)

yobi

\(2^{80}\)

Mass#

gram

\(10^{-3}\) kg

metric_ton

\(10^{3}\) kg

grain

one grain in kg

lb

one pound (avoirdupous) in kg

pound

one pound (avoirdupous) in kg

blob

one inch version of a slug in kg (added in 1.0.0)

slinch

one inch version of a slug in kg (added in 1.0.0)

slug

one slug in kg (added in 1.0.0)

oz

one ounce in kg

ounce

one ounce in kg

stone

one stone in kg

grain

one grain in kg

long_ton

one long ton in kg

short_ton

one short ton in kg

troy_ounce

one Troy ounce in kg

troy_pound

one Troy pound in kg

carat

one carat in kg

m_u

atomic mass constant (in kg)

u

atomic mass constant (in kg)

atomic_mass

atomic mass constant (in kg)

Angle#

degree

degree in radians

arcmin

arc minute in radians

arcminute

arc minute in radians

arcsec

arc second in radians

arcsecond

arc second in radians

Time#

minute

one minute in seconds

hour

one hour in seconds

day

one day in seconds

week

one week in seconds

year

one year (365 days) in seconds

Julian_year

one Julian year (365.25 days) in seconds

Length#

inch

one inch in meters

foot

one foot in meters

yard

one yard in meters

mile

one mile in meters

mil

one mil in meters

pt

one point in meters

point

one point in meters

survey_foot

one survey foot in meters

survey_mile

one survey mile in meters

nautical_mile

one nautical mile in meters

fermi

one Fermi in meters

angstrom

one Angstrom in meters

micron

one micron in meters

au

one astronomical unit in meters

astronomical_unit

one astronomical unit in meters

light_year

one light year in meters

parsec

one parsec in meters

Pressure#

atm

standard atmosphere in pascals

atmosphere

standard atmosphere in pascals

bar

one bar in pascals

torr

one torr (mmHg) in pascals

mmHg

one torr (mmHg) in pascals

psi

one psi in pascals

Area#

hectare

one hectare in square meters

acre

one acre in square meters

Volume#

liter

one liter in cubic meters

litre

one liter in cubic meters

gallon

one gallon (US) in cubic meters

gallon_US

one gallon (US) in cubic meters

gallon_imp

one gallon (UK) in cubic meters

fluid_ounce

one fluid ounce (US) in cubic meters

fluid_ounce_US

one fluid ounce (US) in cubic meters

fluid_ounce_imp

one fluid ounce (UK) in cubic meters

bbl

one barrel in cubic meters

barrel

one barrel in cubic meters

Speed#

kmh

kilometers per hour in meters per second

mph

miles per hour in meters per second

mach

one Mach (approx., at 15 C, 1 atm) in meters per second

speed_of_sound

one Mach (approx., at 15 C, 1 atm) in meters per second

knot

one knot in meters per second

Temperature#

zero_Celsius

zero of Celsius scale in Kelvin

degree_Fahrenheit

one Fahrenheit (only differences) in Kelvins

convert_temperature(val, old_scale, new_scale)

Convert from a temperature scale to another one among Celsius, Kelvin, Fahrenheit, and Rankine scales.

Energy#

eV

one electron volt in Joules

electron_volt

one electron volt in Joules

calorie

one calorie (thermochemical) in Joules

calorie_th

one calorie (thermochemical) in Joules

calorie_IT

one calorie (International Steam Table calorie, 1956) in Joules

erg

one erg in Joules

Btu

one British thermal unit (International Steam Table) in Joules

Btu_IT

one British thermal unit (International Steam Table) in Joules

Btu_th

one British thermal unit (thermochemical) in Joules

ton_TNT

one ton of TNT in Joules

Power#

hp

one horsepower in watts

horsepower

one horsepower in watts

Force#

dyn

one dyne in newtons

dyne

one dyne in newtons

lbf

one pound force in newtons

pound_force

one pound force in newtons

kgf

one kilogram force in newtons

kilogram_force

one kilogram force in newtons

Optics#

lambda2nu(lambda_)

Convert wavelength to optical frequency

nu2lambda(nu)

Convert optical frequency to wavelength.

References#

[CODATA2022 ]

CODATA Recommended Values of the Fundamental Physical Constants 2022.

https://physics.nist.gov/cuu/Constants/