We present an open source software application "BruggemanEstimator" that allows a user to estimate the tortuosity of a porouselectrode. BruggemanEstimator determines the Bruggeman exponent based on the Differential Effective Medium approximation and as input requires only two microscope images: one of the top and one of a cross section through an electrode. These images, which can be easily acquired with a scanning electron or optical microscope, are used to extract a sampling of active particle shapes as well as the orientation of the particles within the electrode. We validate the accuracy of BruggemanEstimator by comparing the estimated Bruggeman exponents to values calculated by performing numerical diffusion simulations on three-dimensional microstructures obtained from tomographic techniques. (C) The Author(s) 2014. Published by ECS.