Lien	Site web	PyPI DLs/month	GitHub Stars	Used by	Built-in units	Built-in constants	Arbitrary prefixes	np scalar array	np object array	Decimal	Fraction	Uncertainties	string	absolute °C	dB	Syntaxe	Commentaires
scipy.constants	scipy.org/...	167 385	7 087	181 360	Oui 50	Oui 400 in CODATA	Non	- no unit objects	- no unit objects	- no unit objects	- no unit objects	- no unit objects	- no unit objects	Non	Non	constants.c == 299792458.0	Just tables of numerical constants; unit-aware calculations not supported. scipy.constants.physical_constants specifies units as strings and uncertainties. Could be used to supply other packages with coefficients.
sympy.physics.units	sympy.org/...	55 424	6 924	18 324	Oui 200?	Oui	- u.mega*u.meter but not u.megameter	Non	Oui array([1, 2, 3])*u.m	- converts to sympy	- converts to sympy					cm = u.m/100
astropy.units	astropy.org/...	11 358	2 435	13 777	Oui	Oui	Non	Oui	-					Oui	Oui	15.1 * u.meter / (32.0 * u.second)
Pint	github.com/...	35 746	1 128	1 579	Oui	Oui	Oui Mm, GV, etc.	Oui array([1,2,3])*ureg.m or ureg.m*array([1,2,3])	Non ValueError	Oui	Oui	Oui built-in	Oui	Oui	Non	V = 1*ureg.dm**3
unyt	readthedocs.io/...		243	29	Oui 101	Oui 33	Oui km									4*m + 3*cm - 5*ft + 6*yard
Quantities	readthedocs.org	3 917	147	231				Oui array([1,2,3]) * pq.J						Non
Units	bitbucket.org/...	1 376
numericalunits	python.org/...	445	69														Overflow issues, random set of units = not deterministic, need to do calculations twice to confirm they are being done correctly
SciMath Units	readthedocs.org/...	430	36									Oui built-in
Buckingham	github.com/...	361	20	0	Oui 53	Non	Oui									V = Number(1,dims='decimeter^3')	Single file
Unum	bitbucket.org/...	334
natu	github.io/...	315			Oui	Oui 40	Oui	Oui m*array([1, 2, 3])	Oui array([1, 2, 3])*m	Non	Non	Oui	Non	Oui	Oui	V = 1*dm**3	weird format for dB, Hz != 1/s, "pre-release state"
misu	github.com/...	308	11	0
Magnitude	juanreyero.com/...	238	16	31	Oui	Oui	Oui
udunitspy	github.com/...	188	2	0													Python wrapper for UDUNITS2
scinumtools.units	github.com/...	0	2		Oui	Oui	Oui	Oui	Oui	Oui	Oui	Oui	Oui	Oui K, Cel, degF, degR	Oui dB, Np, dBm, dBmW, ... (both B and dB)	quant(3, 'J').to('kg*m2/s2') quant([5.9e-4, 5.2e+5], 'J*s-1').to('W') 33*unit('kg'), const('c') 3*unit.m/unit.s	No registries needed like for Pint. Documentation is available here: github.io/...
DimPy	cam.ac.uk/...	0
Scalar	russp.us/...	0
ScientificPython PhysicalQuantities	cnrs-orleans.fr/...	0