Geometrically frustrated systems such as pyrochlore compounds receive much attention since they display exotic magnetic states. The explanation lies on the large degeneracy of the ground state ruled by the subtle balance of magnetic interactions. In this context, the determination of the crystal-electric field (CEF) anisotropy is a major stake. For the R2Ti2O7 series, where R is a rare earth, a simple reliable method using a unique solution of the CEF Hamiltonian allow us to describe all published inelastic neutron spectra and to find with accuracy the spectroscopic g factors. However, for the R2Sn2O7 series we have not succeeded to find a unique solution to describe all the published data. Here, we propose to use the time-of-flight technique on Ho2Sn2O7, Tb2Sn2O7 and Nd2Sn2O7 in order to record a large range of CEF transitions and determine with certainty the CEF states of this series.