  Supersoft X-ray sources (SSSs) are accreting white dwarfs (WDs) with stable
or recurrent thermonuclear burning on their surfaces. High-resolution X-ray
spectra of such objects are rather complex, often consist of several
components, and are difficult to interpret accurately. The main emission source
is the hot surface of the WD and the emergent radiation can potentially be
described by hot WD model atmospheres. We present a new set of such model
atmosphere spectra computed in the effective temperature range from
$100\rm\,kK$ to $1000\rm\,kK$, for eight values of surface gravity and three
different chemical compositions. These compositions correspond to the solar one
as well as to the Large and Small Magellanic Clouds, with decreased heavy
element abundances, at one-half and one-tenth of the solar value. The presented
model grid covers a broad range of physical parameters and, thus, it can be
applied to a wide range of objects. It is also publicly available in
XSPEC~format. As an illustration, we applied it here for the interpretation of
\textit{Chandra} and XMM grating spectra of two classical SSSs, namely, CAL 83
(RX J0543.5$-$6823) and RX J0513.9$-$6951. The obtained effective temperatures
and surface gravities of $T_{\rm eff} \approx 560$ kK, $\log g \approx
8.6-8.7$, and $T_{\rm eff} \approx 630\,{\rm kK}, \log g \approx 8.5-8.6$,
respectively, are in a good agreement with previous estimations for both
sources. The derived WD~mass estimations are within $1.1-1.4\,M_\odot$ for CAL
83 and $1.15-1.4\,M_\odot$ for RX J0513.9$-$6951. The mass of the WD in CAL
$83$ is consistent with the mass predicted from the respective model of
recurrent thermonuclear burning.
