  The hardness of the X-ray spectra of intermediate polars (IPs) is determined
mainly by the white dwarf (WD) compactness (mass-radius ratio, M/R) and, thus,
hard X-ray spectra can be used to constrain the WD mass. An accurate mass
estimate requires the finite size of the WD magnetosphere R_m to be taken into
the account. We suggested to derive it either directly from the observed break
frequency in power spectrum of X-ray or optical lightcurves of a polar, or
assuming the corotation. Here we apply this method to all IPs observed by
NuSTAR (10 objects) and Swift/BAT (35 objects). For the dwarf nova GK Per we
also observe a change of the break frequency with flux, which allows to
constrain the dependence of the magnetosphere radius on the mass-accretion
rate. For our analysis we calculated an additional grid of two-parameter (M and
R_m/R) model spectra assuming a fixed, tall height of the accretion column
H_sh/R=0.25, which is appropriate to determine WD masses in low mass-accretion
IPs like EX\,Hya. Using the Gaia Data Release 2 we obtain for the first time
reliable estimates of the mass-accretion rate and the magnetic field strength
at the WD surface for a large fraction of objects in our sample. We find that
most IPs accrete at rate of ~10^{-9} M_Sun/yr, and have magnetic fields in the
range 1--10 MG. The resulting WD mass average of our sample is 0.79 +/- 0.16
M_Sun, which is consistent with earlier estimates.
