A modified version of the classic Wiley–McLaren time‐of‐flight mass spectrometer (TOFMS) is presented here. Owing to a second‐order compensation of the initial position effect, a mass resolutionm/&dgr;mhigher than 2000 is obtained with large ion volumes, of the order of 0.2 cm3for Na+55(1265 a.m.u.). Sodium clusters Na+nwithnup to 530 (&bartil;12200 a.m.u.) are separated. The spectrometer can be used for the analysis of ionized clusters in a mass range from 1 to about 20000 a.m.u. as well as for the measurement of the kinetic energy of molecular fragments after a Coulomb explosion of a molecule. The performance of this spectrometer is demonstrated with sodium clusters and molecules.