STRIDER, Steric hindrance estimater, is a web server which can estimate and report inter- and intra- molecular steric hindrances based on the atomic van der walls radius of elements, participating in molecule formation. Thus, STRIDER acts as an important tool not only in the modeling of biomacromolecular structures like carbohydrates, lipids, nucleic acids & proteins and their complexes with themselves & small molecules, but also, in the modeling of any chemical structure.