Bio Bidet Toilet Seat Sizes and Compatibility Guide

Interested in purchasing a bidet seat or bidet attachment, but not sure if it will fit your toilet? Use this compatibility guide to measure your toilet and select the seat or attachment that’s right for your bathroom!

Bio Bidet seats and attachments fit on most modern toilets; however, they may not be compatible with some older or specialty models.

Fitting a Bidet: Round vs. Elongated Seats

There are two main types of toilet bowls: elongated and round. Most older, less expensive toilet bowls are round, while more modern, deluxe toilets typically have an elongated bowl.

To accommodate bowls of any shape, we manufacture our most popular bidet seats, including the BB-2000 bidet seat, in both elongated or round. Bidet attachments fit under both elongated and round toilet seats.

How to Tell if a Toilet Is Round or Elongated

Elongated toilets are more oval-shaped than round, as shown in the diagram below. If you're uncertain about which type of seat you have, follow these instructions for measuring your throne.

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 may find it easier to make this measurement and the next one if you remove your toilet seat. You'll 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 with our bidet sizes.
  • 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.
Check to see if your toilet is round or elongated.
Check your compatibility measurements.

The Difference Between One-piece and Two-piece Toilets

In addition to elongated and round toilets, there are also one-piece and two-piece toilets to be aware of. You can tell the difference simply by looking at your toilet:

  • A one-piece toilet is sculpted into a seamless unit and has no crevices between the tank and bowl.
  • A two-piece toilet has a separate tank and bowl that are bolted together upon installation.

Bio Bidet products are designed to fit almost all one-piece and two-piece toilets. However, there are some exceptions, such as certain French curve-style toilets. Bio Bidet seats and attachments don’t fit well on deep French curve toilets as the design and shape of these have limited space near the mounting bolts.

If you have a one-piece toilet with a deep French curve, please contact us with the make and model of your toilet for a compatibility check.

Standard One-Piece Toilet
Standard Two-Piece Toilet
One-Piece Toilet with French Curve

Once you’ve collected all the information you need about your toilet, it’s time to choose your bidet! Browse our selection now to pick the perfect bidet for your home.

Frequently Asked Questions

Can you install a bidet on any toilet?

You can install a bidet on most toilets, but not all! Certain one-piece toilets, like those with a French curve, are not compatible with bidets. Other custom toilet shapes, such as rectangular toilets, may be incompatible with our bidets.

Certain bidet attachment sizes and models may be compatible with custom-shaped toilets. Contact us with your toilet’s dimensions and we can help you check Bio Bidet compatibility.

Do all bidet toilet seats fit all toilets?

No, round and elongated seats are made for round and elongated toilet bowls. You should always match your seat type to your bowl type to avoid damaging your seat or toilet or injuring yourself.

Can you put an elongated toilet seat on a round toilet?

We do not recommend installing seats on non-compatible toilets. The toilet bowl supports the seat, distributing weight and stress across the fixture. If the bowl and seat don’t match up, your bidet seat may break from added stress.

What do I do if my bidet won’t fit with my toilet seat?

Check that all the attachment points are correct and undamaged. If you have a very strangely shaped toilet, you may find that most mainstream bidets aren’t compatible with the fit. You may need to opt for a standard toilet seat that’s compatible with a bidet.

Will a bidet fit my toilet?

If you’re still unsure if our bidets will fit your toilet, contact a customer service representative to get the support you need.

Need to know how to install a bidet? We’ve got you covered.