A one-dimensional numerical code estimating the performances of centrifugal PATs (pumps used as turbines) is presented. Firstly, the code calculates the geometrical components of the PAT using information provided in manufacturer catalogues. Then, once these parameters are deduced, it calculates the losses and determines the characteristics curves of the PAT. The method was validated by comparing the theoretical curves with some experimental measurements acquired at the Department of Mechanical, Energy and Management Engineering (DIMEG) of the University of Calabria, at the Mechanical Propulsion National Centre (CNPM) in Milan and at the University of Trento (Italy) on PATs working in a range of specific speed from 9 to 65 rpm m(3/4) S-1/2. The estimation error was comprised in a range of 5 divided by 20%, generally acceptable for this kind of application. (C) 2016 Elsevier Ltd. All rights reserved.