AbstractA set of formulae are presented that can be used to estimate total well losses when flow into the well is uniformly distributed along its screen. The components of well loss included are: aquifer loss due to partial penetration and non-Darcian flow, loss in the gravel pack, loss through the screen slots, frictional loss in the well casing, and (in particular) loss inside the well screen due to both momentum and frictional loss. The formulae are used to estimate the coefficients of nonlinear well loss for experimental wells constructed in Bangladesh: the values obtained are in good agreement with values determined from step tests on those wells.