In this work, we extend the swelling model introduced by Denton and Tang for ionic microgel in order to incorporate the finite extensibility effects of the polymer chains. With that, we broaden the applicability scope of the model to include both highly charged and short-chain cases, which gains importance when dealing with nanogels and acid-base charge regulation. Besides, we assess the performance of these swelling methods against coarse-grained MD simulations of a single ionic microgel in a wide range of parameters, as a means to elucidate the accuracy of the theoretical models.