diff --git a/sympy/physics/units.py b/sympy/physics/units.py
index b9d145e..b4a1db1 100644
--- a/sympy/physics/units.py
+++ b/sympy/physics/units.py
@@ -163,7 +163,7 @@ u0 = magnetic_constant = 4*pi * ten**-7 * N/A**2
e0 = electric_constant = 1/(u0 * c**2)
Z0 = vacuum_impedance = u0 * c
-planck = Rational('6.2606896') * ten**-34 * J*s
+planck = Rational('6.62606896') * ten**-34 * J*s
hbar = planck / (2*pi)
avogadro = (Rational('6.02214179') * 10**23) / mol
--
1.5.6.5
<pwuertz> thanks for fixing this so quickly!