The Cima-Lopina equation for swelling in hydrogel networks with a bimodal distribution of cross-link densities is modified slightly for an end-linked system. The revised equation is verified with a controllable series of poly(ethylene oxide) hydrogels synthesized from linear and star PEO molecules cross-linked with a triisocyanate linker. Cross-link density in the gels is independently analyzed from elastic modulus and swelling equilibrium. Good correlation between these two methods confirms the accuracy of the revised Cima-Lopina equation.