When creating a mechanical system, it is the act of designing a system beyond the actual expected loads of the system to ensure safety of the system. The design factor is how much stronger the system is than it really needs to be for its actual intended use. Usually it is reported as a ratio such as 5:1 or 10:1. A design factor is used because calculating all of the forces and other factors within a system is often very difficult, if not impossible for very large systems.
