Preheat the oven to 450°F (230°C).
Roll out the pizza dough on a lightly floured surface into a circle, about 1/4 inch thick.
Spread ricotta cheese over half of the dough, leaving a border around the edge.
Top with mozzarella, Parmesan, and sliced pepperoni.
Fold the dough over to create a half-moon shape and crimp the edges to seal.
Transfer the calzone to a baking sheet lined with parchment paper.
Bake for 20-25 minutes or until the crust is golden brown.
Serve hot with tomato sauce on the side for dipping.