Demo

Import module

>>> from electronvolt import *

Rest mass of an electron

>>> me
9.1093837015e-31 * kg

Rest energy of the electron, in SI units

>>> me * c**2
8.187105776823886e-14 * m**2 * s**-2 * kg

In mega electronvolts

>>> me * c**2 / MeV
0.5109989499961642

This matches the electron rest energy on Wikipedia.

Usage

Install via pip install electronvolt.

Alternatively, run this module online

• Typically loads within 3 minutes.
• Shift+enter to run a block of code. Run first block to initialize the calculator.

Units and Constants

Name	Symbol	Value	Unit
Math Constants
	pi	3.141592653589793
Euler's number	euler	2.718281828459045
Metric Prefixes
	yotta	1 e+24
	zetta	1 e+21
	exa	1 e+18
	peta	1 e+15
	tera	1 e+12
	giga	1 e+09
	mega	1000000
	kilo	1000
	hecto	100
	deca	10
	deci	0.1
	centi	0.01
	milli	0.001
	micro	1 e-06
	nano	1 e-09
	pico	1 e-12
	femto	1 e-15
	atto	1 e-18
	zepto	1 e-21
	yocto	1 e-24
Common Prefixes
	hundred	100
	thousand	1000
	million	1000000
	billion	1 e+09
	trillion	1 e+12
SI Base Units
second	s	1	s
meter	m	1	m
kilogram	kg	1	kg
ampere	A	1	A
kelvin	K	1	K
mole	mol	1	mol
candela	cd	1	cd
Time
	minute	60	s
	hour	3600	s
	day	86400	s
	week	604800	s
	year	31557600	s
millisecond	ms	0.001	s
microsecond	us	1 e-06	s
nanosecond	ns	1 e-09	s
Length
kilometer	km	1000	m
decimeter	dm	0.1	m
centimeter	cm	0.01	m
millimeter	mm	0.001	m
micrometer	um	1 e-06	m
nanometer	nm	1 e-09	m
picometer	pm	1 e-12	m
femtometer	fm	1 e-15	m
Frequency
hertz	Hz	1	s-1
kilohertz	kHz	1000	s-1
megahertz	MHz	1000000	s-1
gigahertz	GHz	1 e+09	s-1
terahertz	THz	1 e+12	s-1
Classical Mechanics
gravitational acceleration	g	9.80665	m s-2
newton	N	1	kg m s-2
pascal	Pa	1	kg m-1 s-2
joule	J	1	kg m2 s-2
watt	W	1	kg m2 s-3
Thermodynamics
Planck constant	h	6.62607015 e-34	kg m2 s-1
reduced Planck constant	hbar	1.05457181765 e-34	kg m2 s-1
Avogadro constant	NA	6.02214076 e+23	mol-1
Boltzmann constant	kB	1.380649 e-23	kg m2 s-2 K-1
ideal gas constant	R	8.31446261815324	kg mol-1 K-1 m2 s-2
Electromagnetism
coulomb	C	1	s A
volt	V	1	kg A-1 m2 s-3
farad	F	1	kg-1 A2 m-2 s4
	Ohm	1	kg A-2 m2 s-3
tesla	T	1	kg A-1 s-2
weber	Wb	1	kg m2 s-2 A-1
henry	H	1	kg A-2 m2 s-2
speed of light	c	299792458	m s-1
vacuum magnetic permeability	mu0	1.25663706212 e-06	kg A-2 m s-2
vacuum electric permittivity	epsilon0	8.8541878128 e-12	kg-1 m-3 s4 A2
Coulomb constant	k	8987551792.26078	kg m3 s-4 A-2
elementary charge	e	1.602176634 e-19	s A
Imperial Units
inch ('in' is a python keyword)	in_	0.0254	m
foot	ft	0.3048	m
yard	yd	0.9144	m
mile	mi	1609.344	m
	acre	4046.8564224	m2
nautical mile	NM	1852	m
knot	kn	0.514444444444445	m s-1
US gallon	gal	0.003785411784	m3
pound-mass	lb	0.45359237	kg
pound-force	lbf	4.4482216152605	kg m s-2
	slug	14.59390293720637	kg
	blob	175.1268352464764	kg
Common Units
kilometer per hour	kph	0.277777777777778	m s-1
miles per hour	mph	0.44704	m s-1
	gram	0.001	kg
liter	L	0.001	m3
pound per square inch	psi	6894.757	kg m-1 s-2
kilowatt-hour	kWh	3600000	kg m2 s-2
hectare	ha	10000	m2
Atomic Physics
electron rest mass	me	9.1093837015 e-31	kg
proton mass	mp	1.67262192369 e-27	kg
neutron mass	mn	1.67492749804 e-27	kg
atomic mass unit	u	1.6605390666 e-27	kg
atomic mass of hydrogen	mH	1.6735327848 e-27	kg
atomic mass of helium	mHe	6.64647698905 e-27	kg
Quantum Mechanics
Stefan-Boltzmann constant	sigma	5.67037441918 e-08	kg K-4 s-3
Bohr radius	a0	5.29177210906 e-11	m
hydrogen ground state energy	hground	-2.1798723611 e-18	kg m2 s-2
fine-structure constant	alpha	0.007297352569278
Rydberg constant	Rydberg	10973731.56807162	m-1
Radioactive Decays
becquerel	Bq	1	s-1
curie	Ci	3.7 e+10	s-1
millicurie	mCi	37000000	s-1
microcurie	uCi	37000	s-1
Nuclear Physics
electronvolt	eV	1.602176634 e-19	kg m2 s-2
kilo-electronvolt	keV	1.602176634 e-16	kg m2 s-2
mega-electronvolt	MeV	1.602176634 e-13	kg m2 s-2
giga-electronvolt	GeV	1.602176634 e-10	kg m2 s-2
tera-electronvolt	TeV	1.602176634 e-07	kg m2 s-2
electronvolt per speed of light	eVpc	5.34428599268 e-28	kg m s-1
mega-electronvolt per c	MeVpc	5.34428599268 e-22	kg m s-1
electronvolt per c squared	eVpc2	1.78266192163 e-36	kg
mega-electronvolt per c squared	MeVpc2	1.78266192163 e-30	kg
Cosmology
gravitational constant	G	6.6743 e-11	kg-1 m3 s-2
astronomical unit	au	149597870700	m
light-year	ly	9460730472580800	m
parsec	pc	3.08567758149 e+16	m
megaparsec	Mpc	3.08567758149 e+22	m
Hubble parameter	H0	2.3333610884 e-18	s-1

More Demo

Import ufloat from uncertainties

>>> from uncertainties import ufloat

Rest mass of an electron

>>> me = ufloat(9.1093837015, 0.0000000028) * 1e-31 * kg

Rest energy of the electron

>>> me * c**2
(8.1871057768+/-0.0000000025)e-14 * kg * s**-2 * m**2

This matches the electron rest energy on the same Wikipedia page.