Use the guide below to determine if your toilet is compatible with bidet seats.  The guide will also help you decide whether your toilet bowl shape is round or elongated. If you have a skirted toilet, you'll want to read our article about installing a bidet toilet seat on a skirted toilet first.


Ok, so I want to buy a bidet toilet seat. Where do I start? 

Great! Glad to hear you enjoy feeling clean and are ready to upgrade your throne with a bidet toilet seat.  First, you need to determine what type of toilet you currently have (or whatever toilet you wish to equip).  Toilets come in two basic form factors: the standard 2pc with separate tank and bowl, or the more modern 1pc sculpted unit.



A toilet sculpted into a seamless unit, and has no crevices between the tank and bowl.



This type of toilet has a separate tank and bowl which are bolted together upon installation


Got it. So what does it mean if I have a 1pc or 2pc toilet? 

2 Piece Toilets - You're in luck. Virtually all bidet toilet seats will be able to fit. You simply need to decide whether your bowl is round or elongated.

1 Piece Toilets - Your selection is a bit more limited.  Depending on the actual shape of your 1 piece toilet, a bidet seat may or may not fit. If you're not sure, simply give us a call, or email us a picture of your toilet at - we're here to help. 


If the bowl remains relatively flat and meets the toilet tank at close to a 90 degree angle, a bidet seat should be able to fit. 

1 Piece toilets like the TOTO Ultramax or the Kohler Memoirs are great examples. 

1 piece ok                   

If the tank is curved and meets the bowl on a slope (known as a "french curve") then it is unlikely our bidet seats will fit. 

The Kohler Rialto and San Raphael are popular examples.

1pc x 


Kohler Rialto - Unfortunately, there aren't any models that will fit it 100% correctly. 

Kohler San Raphael - The Alpha JX and Blooming NB-R1063 will fit this toilet nicely about 70% of the time.  There are some versions of the San Raphael that have small changes in molding which prevent any bidet seat from fitting. Unfortunately there's no way to tell if it will work until you have the Alpha JX/Blooming 1063 in front of you. 

Kohler Santa Rosa - The Alpha JX and Blooming NB-R1063 will fit this toilet well, with a 3/4" overhang in front because this is a "compact elongated" toilet bowl, not a true elongated.  


How do I measure my toilet to determine if I have a Round or Elongated bowl?

After you figure out whether you have a 1pc or 2pc toilet, the next step is to determine if your toilet bowl shape is Round or Elongated.  Many of the more modern toilet bowls in the US have the Elongated shape.  Measure your toilet in inches according to the guide below:


toilet dimensions

Line A: Some bidet seats like the Alpha JX need a minimum of 1.5" of clearance from the center of the toilet seat bolt holes, to the front of the toilet tank.  Most other bidet seats need 1.75"

Line B: The distance between the centers of the bolts holes should be between 5.5" and 7.5".  5.5" is the normal standard.

Line C: Elongated bowls have a measurement greater than 18" from the center of the bolt holes to the front of the bowl.  Round bowls have a shorter measurement, usually between 16.5" and 17.5".

Round sized bidet seats are 19.2" in total length.  If your total toilet bowl length (A + C) is less than 19", there will be some overhang in the front of the bowl.  This is common with older round sized toilets.  While the bidet seat will functionally work, it will look awkward.  Elongated sized bidet seats are 20.8" in total length.

Shopping for a new toilet? Check out our BidetKing exclusive Custom Combinations here.  Pair one of our stylish skirted toilets with the bidet seat of your choice and get a bidet toilet combination that's just for you.

We've taken the guesswork of fitment out of the equation so all you have to do is pick your dream bidet combination.

Again, if you're not sure, simply give us a call, or email us a picture of your toilet at - we're here to help.


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