Round toilet bowls measure about 16 1/2 in. From the middle of the mounting bolts to the front of the rim. If your toilet fits this description, buy a round toilet seat.

When purchasing a toilet seat, pay attention to the shape of the toilet bowl, which could be round or elongated. Tighten the plastic bolts with a screwdriver for a secure fit.

To rate each toilet, Consumer Reports’ test engineers put the models through a battery of tests involving waste removal, bowl cleaning, and drain-line clogs.