Given a mapping u: [0,+\infty) to X (here X stands for a complex Banach space) which admits a holomorphic, bounded extension to some sector containing the half axis x<=0, a numerical method for inverting the Laplace transform U(z) of u is presented. The method uses a classical quadrature formula, based on the sinc fonction, and it is shown that the classical estimate O(e^{-c sqrt{n}}) improves to O(e^{-cn}), where n denotes the number of nodes used in the quadrature. One good feature of the method is that the same nodes and evaluations of U can be used for intervals [t_0,t_1] with large ratios t_1/t_0. The influence of the errors in the evalutions of U is also considered.