A statistical model is introduced which allows estimation of the length distribution of meshes in a unimodal polymer network. The length distribution is responsible for the type and number of entanglements in a network and can thus provide information about the deformation behavior of polymers. The model can also predict the influence of certain simulation parameters such as the degree of cross linkage, the chain length, or the density of the melt from which the network is built. Both a reaction- and a diffusion-controlled cross-linking process can be mapped. We found that a shorter chain length implies a smaller number of chains per mesh. An increase of the degree of cross linkage as well as a lowering of the density of the melt also leads to a smaller average length of the meshes.