We perform a complete study of four top quarks production at the LHC in the context of the Standard Model Effective Field Theory (SMEFT). Our analysis is conducted at the tree-level yet investigating all possible QCD- and EW-couplings orders for the contributing dimension-six SMEFT operators. We observe that the formally dominating contributions do not necessarily provide the largest cross-sections and we investigate why. Inclusive and differential predictions are presented for the LHC and the future 100TeV collider scenario. Finally, we carry out a projection study through which we set limits on SMEFT Wilson coefficients at different collider energies for all the relevant SMEFT operators.