Using an exact analytical solution of axisymmetric deformation of a circular membrane centrally connected to a rigid plate under the action of concentrated load at its center, we present an exact formula for the energy release rate applicable to ultrathin film-substrate systems without residual stresses or with small residual stresses. Also, a closed-form solution of axisymmetric deformation of circular membrane under the action of concentrated load at its center is presented. (C) Koninklijke Brill NV, Leiden, 2011