One of the great advantages of dielectric elastomers (DE) is their scalability. This study investigates the influence of size on their performance and the applicability of theory and established models on large-scale actuators. The testing is based on an active hinge configuration made with planar dielectric elastomer actuators as described by Lochmatter in 2007. The actuators are scaled to five times the size of the small hinge which results in planar membrane actuators of 0.95 × 0.25 m. Theoretical aspects of the up-scaling are discussed. The issue of scaling in design and manufacturing of actuators is addressed. A planar test rig for agonist-antagonist activation, comparable to the hinge-configuration, was set up and the actuators were experimentally characterised in terms of strain (deflection angle), blocking force (moment) and input energy. The behaviour of the large actuators could be predicted accurately with an Arruda-Boyce model and they scale according to theory.