The stoichiometry of titanium carbide (TiCx) particles is important in determining particle properties. Spherical TiCx powders with particle sizes of 1–5 μm were produced by self-propagating high-temperature synthesis (SHS) in 30 wt.% Al–, 30 wt.% Cu–, and 30 wt.% Fe–Ti–C systems, respectively. To measure the compositions of the carbide powders, atom probe tomography (APT) tip specimens were carefully prepared by using a focus ion-beam milling method. APT analysis revealed that the TiCx particles formed in Al–, Cu–, and Fe–Ti–C systems are highly substoichiometric. The results are consistent with observations of the TiCx particles with a high content of oxygen and a certain amount of secondary metallic elements (Al, Cu, and Fe).