In actuality, toilet seats don’t come in “sizes”. Instead, they are measured by “shape”.

There are a variety of different types of toilets and along with them are all the different types of toilet seats. Whatever the reason may be that you need to (or want to) replace your toilet seat – you should know the checklist to go through before you head down to your local hardware store to buy your new seat.

Do Toilet Seats Come In Different Sizes?

There are actually only 3 different possible shapes of toilet seats that you can purchase.

  • Round
  • Elongated
  • Square

Although there are 2 types of elongated toilets, both use the same type of toilet seat.

What Are The Toilet Seat Sizes?

Toilet bowls come in the following shapes:

  • Round
  • Elongaged (like an oval shape)
  • Compact Elongated (a shorter oval shape)
  • Square

All round toilet seats will fit all toilets with round bowls. All Elongated toilet seats will fit all toilets with an elongated shape bowl, and so on.

So, before you go to the hardware store to purchase your new toilet seat (or if you order it online), the first thing to know is what is the shape of your toilet bowl?

How Do You Measure For A Toilet Seat Replacement?

Okay so now that you know you need to search for a seat that matches the shape of your toilet bowl, the next question is how to determine the shape.

You do this by taking out your tape measure and measring the bowl itself.

With your measuring tape, measure the distance between the mounting holes at the back of the toilet bowl to the front of the toilet bowl.

  • Round toilet bowls should measure 16 to 17 inches.
  • Elongated toilet bowls should measure 18 to 19 inches.
  • Compact Elongated toilet bowls should measure 18 to 19 inches (the same as standard elongated versions)
  • Square toilet bowls don’t require any measurement since their shape is very evident compared to others

With these measurements in hand, you should be able to successfully purchase your new toilet seat that will fit correctly.

The next decision will be what material should you choose? These days there are soft seats, wooden seats, plastic seats and more.


If you have any questions about toilet seats or toilets or are having some problems with it, call Atlantis Plumbing today at 770-505-8570. We are available 24 hours a day, 7 days a week.