Systems and methods for determining vector-ratio safety factors for wellbore tubular design are provided. Pressure and temperature data for at least one load point along a tubular component of a wellbore are obtained. An effective failure axial load expected at the load point is calculated during a downhole operation to be performed along one or more sections of the wellbore within a subsurface formation, based on the obtained data. An upper boundary and a lower boundary for the effective failure axial load are determined, based on physical properties of the tubular component at the load point. A midpoint of the effective failure axial load is calculated based on the upper and lower boundaries. A critical failure differential pressure is calculated, based on the midpoint of the effective failure axial load. A vector-ratio safety factor is calculated, based on the critical failure differential pressure relative to the effective failure axial load.