Easy 3 Step Fit Guide for Most Bidet Seats

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Step 1: Evaluate Your Toilet Bowl

Step 2: Figure Out if Your Toilet Has a French Curve

Step 3: Decide Whether You Need Additional Hardware

Toilets fall into two categories: one-piece and two-piece. One-piece toilets are sculpted from a single piece of porcelain, giving them a smooth, clean look. Two-piece toilets consist of a base and a tank that are fitted together. Because they come in two pieces, two-piece toilets are easier to maneuver and install than one-piece toilets. They also tend to be less expensive.

One-Piece Toilet
Two Piece Toilet

The good news is that our bidet seats will fit on almost all two-piece toilets and on most one-piece toilets! To ensure a perfect fit, you’ll need to know what type of toilet bowl you have, whether your toilet has a “French curve”, and whether you’ll need a top mounting kit to install your bidet. We cover each of these topics below in three easy steps!

Step 1: Evaluate Your Toilet Bowl

To find a bidet seat that fits your existing toilet perfectly, you’ll need to know whether your toilet (1) has a round or elongated bowl and (2) has enough space in the back.

To figure out if your toilet is round or elongated, measure from the center of the bolt holes to the front edge of the bowl. Round toilets have a circular look and measure about 16.5″ inches from front to back. Elongated toilets have a decidedly oval look and measure around 18.5″ front to back. Since most toilets have an elongated bowl, the majority of bidet seats have an elongated design. Nevertheless there are plenty of bidet models that offer both elongated and round options.

Once you’ve figured out whether your bowl is elongated or round, you’ll need to make sure there’s enough space between the bolt holes and the tank for a bidet to fit. Most bidet seats require a minimum of 1.5 inches between the bolt holes and the tank, but the more room the better. You’ll also need 5.5 inches between the bolt holes.

Check out bidet seats that fit round and elongated toilet

Step 2: Figure Out if Your Toilet Has a French Curve

Next, you’ll need to determine whether your toilet has a French curve (diagram C). On toilets with a French curve, the porcelain arcs down between the tank and the back of the bowl instead of making a right angle (or near-right angle). Our bidet seats will work with most one- and two-piece toilets (diagrams A and B below), but only a handful will fit on toilets with a French curve (diagram C below).

Below are our top recommendations for toilets with a French curve. Keep in mind that some French curve toilets won’t accommodate a bidet at all, so we always encourage customers with this style toilet to contact us before purchasing.

Top Pick: Cascade 3000

Second Place Pick: Blooming R1063 Bidet Seat

Third Place Pick: Galaxy GB-5000 Bidet Seat

Step 3: Decide Whether You Need Additional Hardware

Last but not least, you’ll want to see if you can easily access (1) the underside of your toilet’s bolts and (2) the fill valve under your toilet’s tank. Customers who can’t access either of these may need to purchase additional hardware in order to install their bidet seat.

The toilet’s “trapway” is the winding pipework that the bowl empties into when you flush. The trapway’s raised outline is visible on the side of many toilets, and it’s a prime place for dust and grime to accumulate. Some toilets have a “skirted” design, which means the trapway is filled in, giving the toilet’s pedestal a smooth, streamlined surface.

In addition to looking more modern, skirted toilets are easier to wipe clean than their non-skirted brethren. However, this sleek design also conceals the toilet’s bolt holes, making it tricky to install a bidet seat. The good news is that top mounting kits can solve this issue! These allow you to install a bidet seat without ever having to mess with the underside of the bolt holes.

Standard Bolt Hole Mount (left); Top Mounting Solution (right)

A second problem is that skirted toilets can make it difficult to attach the bidet seat’s T-valve to the fill valve under the tank. To get around this, customers can purchase an alternate T-valve that attaches to the water supply at the wall. This allows you to easily hook up your bidet’s hose without ever having to touch the fill valve!

If you think you might need special hardware, please reach out to us for assistance! While we sell some hardware, there are some situations that may require a product we don’t carry. We want to make sure you get the right hardware for your situation, so we recommend getting in touch before purchasing!

Final Thoughts

Just getting started with Bidets? There’s lots to learn! We have many other great articles under Getting Started With Bidets. We also encourage our customers to reach out to us directly for assistance and support! You can connect with our team of bidet experts in a number of ways: