A crown roller has a larger radius at the center than at the sides. A web in transit through a manufacturing process must be subjected to tension by driven rollers that also maintain web velocity. If the rollers supporting the web were perfectly cylindrical and if the web was perfect in terms of length and thickness uniformity across its width, then the web tension would develop uniform stress in the direction of web travel. When a web encounters a roller that is not perfectly cylindrical and has a crown radius the internal stress becomes non-uniform. This non-uniformity in stress can induce web instability in free web spans or upon roller surfaces which can be detrimental to web quality. The objective of this research is to develop computational tools using FORTRAN that can predict what level of crown in a roller that a given web can transit without becoming unstable.