The possibility of detecting neutrinoless double-$\ensuremath{\beta}$-decay (0$\ensuremath{\nu}\ensuremath{\beta}\ensuremath{\beta}$-decay) in experiments that are currently in operation or under development provides the exciting opportunity to determine the Dirac or Majorana nature of the neutrino and its absolute mass scale. An important datum for interpreting 0$\ensuremath{\nu}\ensuremath{\beta}\ensuremath{\beta}$-decay experimental results is the $Q$ value of the decay. Using Penning trap mass spectrometry we have measured the atomic mass of ${}^{48}$Ca to be $M{[}^{48}$Ca] $=$ 47.952 522 76(21) u which, combined with the mass of ${}^{48}$Ti evaluated by Audi et al. [Nucl. Phys. A 729, 337 (2003)], provides a new determination of the ${}^{48}$Ca $\ensuremath{\beta}\ensuremath{\beta}$-decay $Q$ value: ${Q}_{\ensuremath{\beta}\ensuremath{\beta}}$ $=$ 4262.96(84) keV.