Fast level set methods replace continuous PDEs by a discrete formulation, improving the execution times. The regularization in fast level set methods was so far handled indirectly via level set function smoothing. We propose to incorporate standard curvature based regularization into fast level set methods and address the problem of efficiently estimating local curvature of a discretized interface in 2D or 3D based on local partial volume. We present two algorithms for incremental partial volume evaluation: the first is recommended for moderate neighborhood sizes, the second has an excellent asymptotic complexity and can be useful for very large neighborhoods. The performance of the proposed methods is compared experimentally with previous approaches.