Constants (scipy.constants)#
Physical and mathematical constants and units.
Mathematical constants#
  | 
Pi  | 
  | 
Golden ratio  | 
  | 
Golden ratio  | 
Physical constants#
  | 
speed of light in vacuum  | 
  | 
speed of light in vacuum  | 
  | 
the magnetic constant \(\mu_0\)  | 
  | 
the electric constant (vacuum permittivity), \(\epsilon_0\)  | 
  | 
the Planck constant \(h\)  | 
  | 
the Planck constant \(h\)  | 
  | 
\(\hbar = h/(2\pi)\)  | 
  | 
Newtonian constant of gravitation  | 
  | 
Newtonian constant of gravitation  | 
  | 
standard acceleration of gravity  | 
  | 
elementary charge  | 
  | 
elementary charge  | 
  | 
molar gas constant  | 
  | 
molar gas constant  | 
  | 
fine-structure constant  | 
  | 
fine-structure constant  | 
  | 
Avogadro constant  | 
  | 
Avogadro constant  | 
  | 
Boltzmann constant  | 
  | 
Boltzmann constant  | 
  | 
Stefan-Boltzmann constant \(\sigma\)  | 
  | 
Stefan-Boltzmann constant \(\sigma\)  | 
  | 
Wien displacement law constant  | 
  | 
Rydberg constant  | 
  | 
electron mass  | 
  | 
electron mass  | 
  | 
proton mass  | 
  | 
proton mass  | 
  | 
neutron mass  | 
  | 
neutron mass  | 
Constants database#
In addition to the above variables, scipy.constants also contains the
2018 CODATA recommended values [CODATA2018] database containing more physical
constants.
  | 
Value in physical_constants indexed by key  | 
  | 
Unit in physical_constants indexed by key  | 
  | 
Relative precision in physical_constants indexed by key  | 
  | 
Return list of physical_constant keys containing a given string.  | 
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).
Available constants:
  | 
6.6446573357e-27 kg  | 
  | 
5.9719201914e-10 J  | 
  | 
3727.3794066 MeV  | 
  | 
4.001506179127 u  | 
  | 
0.0040015061777 kg mol^-1  | 
  | 
4.001506179127  | 
  | 
7294.29954142  | 
  | 
3.97259969009  | 
  | 
1.00001495e-10 m  | 
  | 
1.6605390666e-27 kg  | 
  | 
1.4924180856e-10 J  | 
  | 
931.49410242 MeV  | 
  | 
931494102.42 eV  | 
  | 
34231776.874 E_h  | 
  | 
2.25234271871e+23 Hz  | 
  | 
751300661040000.0 m^-1  | 
  | 
1.4924180856e-10 J  | 
  | 
10809540191600.0 K  | 
  | 
1.6605390666e-27 kg  | 
  | 
3.2063613061e-53 C^3 m^3 J^-2  | 
  | 
6.2353799905e-65 C^4 m^4 J^-3  | 
  | 
1.054571817e-34 J s  | 
  | 
1.602176634e-19 C  | 
  | 
1081202384570.0 C m^-3  | 
  | 
0.00662361823751 A  | 
  | 
8.4783536255e-30 C m  | 
  | 
514220674763.0 V m^-1  | 
  | 
9.7173624292e+21 V m^-2  | 
  | 
1.64877727436e-41 C^2 m^2 J^-1  | 
  | 
27.211386245988 V  | 
  | 
4.4865515246e-40 C m^2  | 
  | 
4.3597447222071e-18 J  | 
  | 
8.2387234983e-08 N  | 
  | 
5.29177210903e-11 m  | 
  | 
1.85480201566e-23 J T^-1  | 
  | 
235051.756758 T  | 
  | 
7.8910366008e-29 J T^-2  | 
  | 
9.1093837015e-31 kg  | 
  | 
1.9928519141e-24 kg m s^-1  | 
  | 
1.11265005545e-10 F m^-1  | 
  | 
2.4188843265857e-17 s  | 
  | 
2187691.26364 m s^-1  | 
  | 
6.02214076e+23 mol^-1  | 
  | 
9.2740100783e-24 J T^-1  | 
  | 
5.788381806e-05 eV T^-1  | 
  | 
13996244936.1 Hz T^-1  | 
  | 
46.686447783 m^-1 T^-1  | 
  | 
0.67171381563 K T^-1  | 
  | 
5.29177210903e-11 m  | 
  | 
1.380649e-23 J K^-1  | 
  | 
8.617333262e-05 eV K^-1  | 
  | 
20836619120.0 Hz K^-1  | 
  | 
69.50348004 m^-1 K^-1  | 
  | 
376.730313668 ohm  | 
  | 
2.8179403262e-15 m  | 
  | 
2.42631023867e-12 m  | 
  | 
7.748091729e-05 S  | 
  | 
1.00000008887 A  | 
  | 
1.00000008887 C  | 
  | 
0.9999999822 F  | 
  | 
1.00000001779 H  | 
  | 
483597900000000.0 Hz V^-1  | 
  | 
1.00000001779 ohm  | 
  | 
1.00000010666 V  | 
  | 
25812.807 ohm  | 
  | 
1.00000019553 W  | 
  | 
1.00207697e-13 m  | 
  | 
0.8574382338  | 
  | 
4.330735094e-27 J T^-1  | 
  | 
0.000466975457  | 
  | 
0.8574382338  | 
  | 
3.3435837724e-27 kg  | 
  | 
3.00506323102e-10 J  | 
  | 
1875.61294257 MeV  | 
  | 
2.013553212745 u  | 
  | 
0.00201355321205 kg mol^-1  | 
  | 
2.013553212745  | 
  | 
2.12799e-15 m  | 
  | 
-0.0004664345551  | 
  | 
3670.48296788  | 
  | 
-0.44820653  | 
  | 
0.30701220939  | 
  | 
1.99900750139  | 
  | 
-175882001076.0 C kg^-1  | 
  | 
-2.00231930436256  | 
  | 
176085963023.0 s^-1 T^-1  | 
  | 
28024.9514242 MHz T^-1  | 
  | 
-9.2847647043e-24 J T^-1  | 
  | 
0.00115965218128  | 
  | 
-1.00115965218128  | 
  | 
-1838.28197188  | 
  | 
9.1093837015e-31 kg  | 
  | 
8.1871057769e-14 J  | 
  | 
0.51099895 MeV  | 
  | 
0.000548579909065 u  | 
  | 
5.4857990888e-07 kg mol^-1  | 
  | 
0.000548579909065  | 
  | 
0.0001370933554787  | 
  | 
864.058257  | 
  | 
-658.2275971  | 
  | 
1.602176634e-19 J  | 
  | 
1.07354410233e-09 u  | 
  | 
0.036749322175655 E_h  | 
  | 
241798924200000.0 Hz  | 
  | 
806554.3937 m^-1  | 
  | 
1.602176634e-19 J  | 
  | 
11604.51812 K  | 
  | 
1.782661921e-36 kg  | 
  | 
-2143.9234915  | 
  | 
0.0002724437107462  | 
  | 
0.0001819543074573  | 
  | 
206.7669883  | 
  | 
0.00483633169  | 
  | 
960.9205  | 
  | 
0.00054386734424  | 
  | 
-658.21068789  | 
  | 
0.000544617021487  | 
  | 
0.000287585  | 
  | 
0.0001819200062251  | 
  | 
1.602176634e-19 C  | 
  | 
1519267447000000.0 A J^-1  | 
  | 
96485.33212 C mol^-1  | 
  | 
1.1663787e-05 GeV^-2  | 
  | 
0.0072973525693  | 
  | 
3.741771852e-16 W m^2  | 
  | 
1.191042972e-16 W m^2 sr^-1  | 
  | 
4.3597447222071e-18 J  | 
  | 
27.211386245988 eV  | 
  | 
2.92126232205e-08 u  | 
  | 
27.211386245988 eV  | 
  | 
6579683920502000.0 Hz  | 
  | 
21947463.13632 m^-1  | 
  | 
4.3597447222071e-18 J  | 
  | 
315775.02480407 K  | 
  | 
4.8508702095432e-35 kg  | 
  | 
-4.255250615  | 
  | 
-1.074617532e-26 J T^-1  | 
  | 
-0.001158740958  | 
  | 
-2.127625307  | 
  | 
5.0064127796e-27 kg  | 
  | 
4.4995394125e-10 J  | 
  | 
2808.39160743 MeV  | 
  | 
3.014932247175 u  | 
  | 
0.00301493224613 kg mol^-1  | 
  | 
3.014932247175  | 
  | 
5.996743e-05  | 
  | 
5495.88528007  | 
  | 
2.99315267167  | 
  | 
4.4398216652e-24 u  | 
  | 
4.135667696e-15 eV  | 
  | 
1.519829846057e-16 E_h  | 
  | 
3.3356409519815204e-09 m^-1  | 
  | 
6.62607015e-34 J  | 
  | 
4.799243073e-11 K  | 
  | 
7.372497323e-51 kg  | 
  | 
9192631770.0 Hz  | 
  | 
137.035999084  | 
  | 
1.3310250501e-15 u  | 
  | 
1.239841984e-06 eV  | 
  | 
4.556335252912e-08 E_h  | 
  | 
299792458.0 Hz  | 
  | 
1.986445857e-25 J  | 
  | 
0.01438776877 K  | 
  | 
2.210219094e-42 kg  | 
  | 
12906.40372 ohm  | 
  | 
483597848400000.0 Hz V^-1  | 
  | 
6700535256.5 u  | 
  | 
6.241509074e+18 eV  | 
  | 
2.2937122783963e+17 E_h  | 
  | 
1.509190179e+33 Hz  | 
  | 
5.034116567e+24 m^-1  | 
  | 
7.242970516e+22 K  | 
  | 
1.1126500560536185e-17 kg  | 
  | 
9.2510873014e-14 u  | 
  | 
8.617333262e-05 eV  | 
  | 
3.1668115634556e-06 E_h  | 
  | 
20836619120.0 Hz  | 
  | 
69.50348004 m^-1  | 
  | 
1.380649e-23 J  | 
  | 
1.536179187e-40 kg  | 
  | 
6.0221407621e+26 u  | 
  | 
5.609588603e+35 eV  | 
  | 
2.0614857887409e+34 E_h  | 
  | 
1.356392489e+50 Hz  | 
  | 
4.524438335e+41 m^-1  | 
  | 
8.987551787368176e+16 J  | 
  | 
6.50965726e+39 K  | 
  | 
5.431020511e-10 m  | 
  | 
1.920155716e-10 m  | 
  | 
2.651645804e+25 m^-3  | 
  | 
2.686780111e+25 m^-3  | 
  | 
683.0 lm W^-1  | 
  | 
2.067833848e-15 Wb  | 
  | 
1.00209952e-13 m  | 
  | 
8.314462618 J mol^-1 K^-1  | 
  | 
0.00099999999965 kg mol^-1  | 
  | 
0.0119999999958 kg mol^-1  | 
  | 
3.990312712e-10 J Hz^-1 mol^-1  | 
  | 
0.02271095464 m^3 mol^-1  | 
  | 
0.02241396954 m^3 mol^-1  | 
  | 
1.205883199e-05 m^3 mol^-1  | 
  | 
1.17344411e-14 m  | 
  | 
-2.0023318418  | 
  | 
-4.4904483e-26 J T^-1  | 
  | 
0.00116592089  | 
  | 
-0.00484197047  | 
  | 
-8.89059703  | 
  | 
1.883531627e-28 kg  | 
  | 
1.692833804e-11 J  | 
  | 
105.6583755 MeV  | 
  | 
0.1134289259 u  | 
  | 
0.0001134289259 kg mol^-1  | 
  | 
206.768283  | 
  | 
0.112454517  | 
  | 
-3.183345142  | 
  | 
0.1126095264  | 
  | 
0.0594635  | 
  | 
1.054571817e-34 J s  | 
  | 
6.582119569e-16 eV s  | 
  | 
8.1871057769e-14 J  | 
  | 
0.51099895 MeV  | 
  | 
3.8615926796e-13 m  | 
  | 
9.1093837015e-31 kg  | 
  | 
2.730924488e-22 kg m s^-1  | 
  | 
0.5109989461 MeV/c  | 
  | 
1.28808866819e-21 s  | 
  | 
299792458.0 m s^-1  | 
  | 
1.31959090581e-15 m  | 
  | 
-3.82608545  | 
  | 
183247171.0 s^-1 T^-1  | 
  | 
29.1646931 MHz T^-1  | 
  | 
-9.6623651e-27 J T^-1  | 
  | 
-0.00104187563  | 
  | 
-1.91304273  | 
  | 
1.67492749804e-27 kg  | 
  | 
1.50534976287e-10 J  | 
  | 
939.56542052 MeV  | 
  | 
1.00866491595 u  | 
  | 
0.0010086649156 kg mol^-1  | 
  | 
1.00866491595  | 
  | 
-0.68499694  | 
  | 
0.00104066882  | 
  | 
1838.68366173  | 
  | 
8.89248406  | 
  | 
-0.68497934  | 
  | 
2.30557435e-30 kg  | 
  | 
2.07214689e-13 J  | 
  | 
1.29333236 MeV  | 
  | 
0.00138844933 u  | 
  | 
1.00137841931  | 
  | 
0.528779  | 
  | 
6.6743e-11 m^3 kg^-1 s^-2  | 
  | 
6.70883e-39 (GeV/c^2)^-2  | 
  | 
5.0507837461e-27 J T^-1  | 
  | 
3.15245125844e-08 eV T^-1  | 
  | 
0.0254262341353 m^-1 T^-1  | 
  | 
0.00036582677756 K T^-1  | 
  | 
7.6225932291 MHz T^-1  | 
  | 
6.62607015e-34 J Hz^-1  | 
  | 
4.135667696e-15 eV Hz^-1  | 
  | 
1.616255e-35 m  | 
  | 
2.176434e-08 kg  | 
  | 
1.22089e+19 GeV  | 
  | 
1.416784e+32 K  | 
  | 
5.391247e-44 s  | 
  | 
95788331.56 C kg^-1  | 
  | 
1.32140985539e-15 m  | 
  | 
5.5856946893  | 
  | 
267522187.44 s^-1 T^-1  | 
  | 
42.577478518 MHz T^-1  | 
  | 
1.41060679736e-26 J T^-1  | 
  | 
0.0015210322023  | 
  | 
2.79284734463  | 
  | 
2.5689e-05  | 
  | 
1.67262192369e-27 kg  | 
  | 
1.50327761598e-10 J  | 
  | 
938.27208816 MeV  | 
  | 
1.007276466621 u  | 
  | 
0.00100727646627 kg mol^-1  | 
  | 
1.007276466621  | 
  | 
8.414e-16 m  | 
  | 
1836.15267343  | 
  | 
8.88024337  | 
  | 
-1.45989805  | 
  | 
0.99862347812  | 
  | 
0.528051  | 
  | 
0.00036369475516 m^2 s^-1  | 
  | 
0.00072738951032 m^2 s^-1  | 
  | 
3.8615926796e-13 m  | 
  | 
1.867594306e-15 m  | 
  | 
2.1001941552e-16 m  | 
  | 
1.054571817e-34 J s  | 
  | 
6.582119569e-16 eV s  | 
  | 
197.3269804 MeV fm  | 
  | 
2.10308910336e-16 m  | 
  | 
1.110538e-16 m  | 
  | 
10973731.56816 m^-1  | 
  | 
3289841960250800.0 Hz  | 
  | 
13.605693122994 eV  | 
  | 
2.1798723611035e-18 J  | 
  | 
-1.15170753706  | 
  | 
-1.16487052358  | 
  | 
0.01438776877 m K  | 
  | 
203789456.9 s^-1 T^-1  | 
  | 
32.43409942 MHz T^-1  | 
  | 
-1.07455309e-26 J T^-1  | 
  | 
-0.001158671471  | 
  | 
-2.127497719  | 
  | 
-0.7617665618  | 
  | 
-0.7617861313  | 
  | 
267515315.1 s^-1 T^-1  | 
  | 
42.57638474 MHz T^-1  | 
  | 
1.41057056e-26 J T^-1  | 
  | 
0.001520993128  | 
  | 
2.792775599  | 
  | 
2.02e-08  | 
  | 
2.414e-08  | 
  | 
299792458.0 m s^-1  | 
  | 
9.80665 m s^-2  | 
  | 
101325.0 Pa  | 
  | 
100000.0 Pa  | 
  | 
5.670374419e-08 W m^-2 K^-4  | 
  | 
6.97771e-16 m  | 
  | 
1776.86 MeV  | 
  | 
3.16754e-27 kg  | 
  | 
2.84684e-10 J  | 
  | 
1.90754 u  | 
  | 
0.00190754 kg mol^-1  | 
  | 
3477.23  | 
  | 
16.817  | 
  | 
1.89115  | 
  | 
1.89376  | 
  | 
6.6524587321e-29 m^2  | 
  | 
5.957924931  | 
  | 
1.5046095202e-26 J T^-1  | 
  | 
0.0016223936651  | 
  | 
2.9789624656  | 
  | 
5.0073567446e-27 kg  | 
  | 
4.500387806e-10 J  | 
  | 
2808.92113298 MeV  | 
  | 
3.01550071621 u  | 
  | 
0.00301550071517 kg mol^-1  | 
  | 
3.01550071621  | 
  | 
1.0666399191  | 
  | 
5496.92153573  | 
  | 
2.99371703414  | 
  | 
1.6605390666e-27 kg  | 
  | 
8.8541878128e-12 F m^-1  | 
  | 
1.25663706212e-06 N A^-2  | 
  | 
25812.80745 ohm  | 
  | 
0.88153  | 
  | 
0.2229  | 
  | 
58789257570.0 Hz K^-1  | 
  | 
0.002897771955 m K  | 
Units#
SI prefixes#
  | 
\(10^{30}\)  | 
  | 
\(10^{27}\)  | 
  | 
\(10^{24}\)  | 
  | 
\(10^{21}\)  | 
  | 
\(10^{18}\)  | 
  | 
\(10^{15}\)  | 
  | 
\(10^{12}\)  | 
  | 
\(10^{9}\)  | 
  | 
\(10^{6}\)  | 
  | 
\(10^{3}\)  | 
  | 
\(10^{2}\)  | 
  | 
\(10^{1}\)  | 
  | 
\(10^{-1}\)  | 
  | 
\(10^{-2}\)  | 
  | 
\(10^{-3}\)  | 
  | 
\(10^{-6}\)  | 
  | 
\(10^{-9}\)  | 
  | 
\(10^{-12}\)  | 
  | 
\(10^{-15}\)  | 
  | 
\(10^{-18}\)  | 
  | 
\(10^{-21}\)  | 
  | 
\(10^{-24}\)  | 
  | 
\(10^{-27}\)  | 
  | 
\(10^{-30}\)  | 
Binary prefixes#
  | 
\(2^{10}\)  | 
  | 
\(2^{20}\)  | 
  | 
\(2^{30}\)  | 
  | 
\(2^{40}\)  | 
  | 
\(2^{50}\)  | 
  | 
\(2^{60}\)  | 
  | 
\(2^{70}\)  | 
  | 
\(2^{80}\)  | 
Mass#
  | 
\(10^{-3}\) kg  | 
  | 
\(10^{3}\) kg  | 
  | 
one grain in kg  | 
  | 
one pound (avoirdupous) in kg  | 
  | 
one pound (avoirdupous) in kg  | 
  | 
one inch version of a slug in kg (added in 1.0.0)  | 
  | 
one inch version of a slug in kg (added in 1.0.0)  | 
  | 
one slug in kg (added in 1.0.0)  | 
  | 
one ounce in kg  | 
  | 
one ounce in kg  | 
  | 
one stone in kg  | 
  | 
one grain in kg  | 
  | 
one long ton in kg  | 
  | 
one short ton in kg  | 
  | 
one Troy ounce in kg  | 
  | 
one Troy pound in kg  | 
  | 
one carat in kg  | 
  | 
atomic mass constant (in kg)  | 
  | 
atomic mass constant (in kg)  | 
  | 
atomic mass constant (in kg)  | 
Angle#
  | 
degree in radians  | 
  | 
arc minute in radians  | 
  | 
arc minute in radians  | 
  | 
arc second in radians  | 
  | 
arc second in radians  | 
Time#
  | 
one minute in seconds  | 
  | 
one hour in seconds  | 
  | 
one day in seconds  | 
  | 
one week in seconds  | 
  | 
one year (365 days) in seconds  | 
  | 
one Julian year (365.25 days) in seconds  | 
Length#
  | 
one inch in meters  | 
  | 
one foot in meters  | 
  | 
one yard in meters  | 
  | 
one mile in meters  | 
  | 
one mil in meters  | 
  | 
one point in meters  | 
  | 
one point in meters  | 
  | 
one survey foot in meters  | 
  | 
one survey mile in meters  | 
  | 
one nautical mile in meters  | 
  | 
one Fermi in meters  | 
  | 
one Angstrom in meters  | 
  | 
one micron in meters  | 
  | 
one astronomical unit in meters  | 
  | 
one astronomical unit in meters  | 
  | 
one light year in meters  | 
  | 
one parsec in meters  | 
Pressure#
  | 
standard atmosphere in pascals  | 
  | 
standard atmosphere in pascals  | 
  | 
one bar in pascals  | 
  | 
one torr (mmHg) in pascals  | 
  | 
one torr (mmHg) in pascals  | 
  | 
one psi in pascals  | 
Area#
  | 
one hectare in square meters  | 
  | 
one acre in square meters  | 
Volume#
  | 
one liter in cubic meters  | 
  | 
one liter in cubic meters  | 
  | 
one gallon (US) in cubic meters  | 
  | 
one gallon (US) in cubic meters  | 
  | 
one gallon (UK) in cubic meters  | 
  | 
one fluid ounce (US) in cubic meters  | 
  | 
one fluid ounce (US) in cubic meters  | 
  | 
one fluid ounce (UK) in cubic meters  | 
  | 
one barrel in cubic meters  | 
  | 
one barrel in cubic meters  | 
Speed#
  | 
kilometers per hour in meters per second  | 
  | 
miles per hour in meters per second  | 
  | 
one Mach (approx., at 15 C, 1 atm) in meters per second  | 
  | 
one Mach (approx., at 15 C, 1 atm) in meters per second  | 
  | 
one knot in meters per second  | 
Temperature#
  | 
zero of Celsius scale in Kelvin  | 
  | 
one Fahrenheit (only differences) in Kelvins  | 
  | 
Convert from a temperature scale to another one among Celsius, Kelvin, Fahrenheit, and Rankine scales.  | 
Energy#
  | 
one electron volt in Joules  | 
  | 
one electron volt in Joules  | 
  | 
one calorie (thermochemical) in Joules  | 
  | 
one calorie (thermochemical) in Joules  | 
  | 
one calorie (International Steam Table calorie, 1956) in Joules  | 
  | 
one erg in Joules  | 
  | 
one British thermal unit (International Steam Table) in Joules  | 
  | 
one British thermal unit (International Steam Table) in Joules  | 
  | 
one British thermal unit (thermochemical) in Joules  | 
  | 
one ton of TNT in Joules  | 
Power#
  | 
one horsepower in watts  | 
  | 
one horsepower in watts  | 
Force#
  | 
one dyne in newtons  | 
  | 
one dyne in newtons  | 
  | 
one pound force in newtons  | 
  | 
one pound force in newtons  | 
  | 
one kilogram force in newtons  | 
  | 
one kilogram force in newtons  | 
Optics#
  | 
Convert wavelength to optical frequency  | 
  | 
Convert optical frequency to wavelength.  | 
References#
CODATA Recommended Values of the Fundamental Physical Constants 2018.