As CMOS technology scaling continues, leakage current is increasingly degrading energy efficiency. The leakage problem can potentially be addressed by nanoelectromechanical (NEMS) relay technology, where the off state leakage current is virtually zero. These devices incorporate a suspended nanobeam which is drawn across a gap to make contact in similar fashion to a traditional relay. The properties of this nanobeam must be carefully engineered to minimise stiffness (hence operating voltage), while simultaneously maintaining sufficient restoring force to overcome the adhesion forces at the contact surface which are significant at the nanoscale. To engineer the beam stiffness, detailed understanding of the beam composition and geometry, combined with accurate modelling is required. Simple analytical models over-estimate the stiffness of the cantilever beam along its length, and both analytical and FEA models which account for the manufacturing induced geometrical complexity are required. In this work, spatial force mapping of fabricated beams was used to experimentally validate analytical and FEA models incorporating detailed beam dimensions. An excellent fit was achieved, and this provides a method for targeting beam properties in a NEMS device.