  We calculate scalar static polarizabilities for lanthanides and actinides,
the atoms with open $4f$ or $5f$ subshell. We show that polarizabilities of the
low states are approximately the same for all states of given configuration and
present a way of calculating them reducing valence space to just two or three
valence electrons occupying $6s$ and $5d$ states for lanthanides or $7s$ and
$6d$ states for actinides while $4f$ and $5f$ states are considered to be in
the core. Configuration interaction technique is used to calculate
polarizabilities of lanthanides and actinides for all states of the $4f^n6s^2$
and $4f^{n-1}6s^25d$ configurations of lanthanides and all states of the
$5f^{n}7s^2$ and $5f^{n-1}7s^26d$ configurations of actinides. Polarizability
of the electron core (including f-orbitals) has been calculated in the RPA
approximation.
