  The investigation of the absolute scale of the effective neutrino mass
remains challenging due to the exclusively weak interaction of neutrinos with
all known particles in the standard model of particle physics. Currently, the
most precise and least model-dependent upper limit on the electron antineutrino
mass is set by the KATRIN experiment from the analysis of the tritium
\b{eta}-decay. Another promising approach is the electron capture in
$^{163}\mathrm{Ho}$, which is under investigation using microcalorimetry within
the ECHo and HOLMES collab orations. An independently measured Q-value of this
process is vital for the assessment of systematic uncertainties in the neutrino
mass determination. Here, we report a direct, independent determination of this
$Q$-value by measuring the free-space cyclotron frequency ratio of highly
charged ions of $^{163}\mathrm{Ho}$ and $^{163}\mathrm{Dy}$ in the Penning trap
experiment \textsc{Pentatrap}. Combining this ratio with atomic physics
calculations of the electronic binding energies yields a $Q$-value of
$2863.2(0.6)\,\mathrm{eV}/c^{2}$ - a more than 50-fold improvement over the
state-of-the-art. This will enable the determination of the electron neutrino
mass on a sub-eV level from the analysis of the electron capture in
$^{163}\mathrm{Ho}$.
