There are two main types of toilet bowls: elongated and round. Older and more basic toilets are round, while more modern, deluxe toilets have an elongated bowl.
Elongated toilets are more oval-shaped than round, as shown in the diagram below. If you're uncertain about which type you have – here’s how to measure your toilet for a bidet seat or attachment:
- To measure the length of the bowl, locate the two mounting bolts at the seat hinge. From there, measure to the very front of the toilet bowl in a straight line. That straight line measurement will be about 16-1/2 inches if the bowl is round, and 18-1/2 inches if your bowl is elongated.
- You'll also need to measure the distance between the toilet bolt holes. Any distance shorter than 5.5 inches or greater than 7.5 inches will likely be incompatible.
- The last measurement you’ll need to confirm is the distance between the bolt holes and the toilet tank, which should be no less than 1.5 inches.