When someone decides to buy a bidet toilet seat, it's often the first time they've ever taken a hard look at their current toilet.  You use your toilet multiple times a day, but it's only until you start shopping for a bidet seat that you realize how many different kinds of toilets exist.  Toilet bowls come in two main shapes: elongated or round. As a result, bidet toilet seats also come in elongated or round sizes. All bidet seats are available in the elongated size, but only some are available in round.  So what do you do if you have a round toilet? Can an elongated bidet seat be installed on a round toilet? In this article we will discuss the possibilities and outcomes of putting an elongated bidet seat on a round toilet.


Toilet Measurement


Toilet and Bidet Seat Measurements

A standard round toilet bowl, when measuring from the seat bolt holes to the front lip of the bowl (C), measures about 16.5”.  This means that the total length of the bowl (A+C) is about 18” - 19.5”. A round size bidet seat is usually 19.25” in total length.

A standard elongated toilet bowl, with the same measuring points, usually comes in between 18” - 19” for measurement (C) and 20”-22” in total bowl length (A+C). An elongated size bidet seat is usually 20.75” in total length.  

There is a clear distinction in bowl length between the two toilet sizes from 1.5” to 2.5”. This difference in length will also be found when purchasing a bidet seat. Elongated bidet seats and round versions share the same rear end where all the internal components are stored.  The only difference is found in the length of the actual seat and lid portion. This means that either size bidet seat will be able to mount on either size toilet. So, what’s the issue when trying to put on an elongated bidet seat on a round toilet?

Round and Elongated Toilet

The main issue with putting an elongated bidet seat on a round toilet is overhang. Any elongated bidet seat on a round toilet will overhang, or overlap on a round toilet’s rim by 1.5” - 2.5”.  This is assuming the bidet seat is already mounted all the way back against the tank.

First, the overhang is aesthetically displeasing as it creates an awkward looking toilet setup.  The bigger issue is that this setup means the front lip of your toilet bowl will be visible when looking down inside the bidet seat.  If the round toilet bowl is especially short like on older toilets, it creates a small gap between the rim of the bowl and the elongated bidet seat’s opening as pictured.  It may cause some discomfort when sitting (especially for males) and adds the potential for “splashing out” during a cleansing wash. Lastly, having this 1.5” to 2.5” overhang can cause extra stress to the front portion of the bidet’s seat if the user puts too much weight on it. 


Elongated Bidet Seat on Round Toilet


Should You Put an Elongated Bidet on a Round Toilet?

In short, we don’t recommend it due to the issues described above.  Are there situations where it’s ok? If the user currently has a round toilet and is going to move the bidet seat to an elongated toilet in the near future, then it can work as a temporary solution so long as the user is aware of and careful about the issues described.  An elongated bidet seat will still mount on a round toilet, as well as function just fine, but the aesthetics and comfort of the seat will be greatly diminished.

Are There Any Solutions?

The two solutions are to either swap the toilet for a different sized toilet, or convert the bidet seat to the other size.  Many bidets seats come in both round and elongated sizes. If so, it’s possible to convert it to a different size by swapping out the seat and lid portions.