Although a number of theories exist to quantify the entropy difference between face-on and side-on interface configurations, a simple, accurate, analytical expression for the entropy as a function of system parameters is lacking, and a nematic bulk phase is often assumed. Instead, we have taken a semi-empirical approach, in which the entropy difference is measured in a comparatively small number of MD simulations of purely repulsive particles, to obtain a universal scaling relationship at the solid and vapour interfaces. Due to the absence of attractive interactions, any alignment of the purely repulsive particles at the solid or vapour interfaces can, to a good approximation, be attributed entirely to entropy. The Helmholtz free energy difference between two states of a system can be calculated as ∆F = ∆U -T ∆S, which in the absence of an energetic contribution (∆U = 0) gives ∆F = -T ∆S. The entropy difference per interface particle between states of a system in the NVT ensemble with perfectly face-on and side-on orientations at an interface can then be estimated as