So you’re just about done researching your next bidet toilet seat. You’ve narrowed it down to two choices. You know both of these bidet seats have adjustable wash nozzles and a warmed toilet seat. You know they have massage and water pulsation features. But do you know if these bidets will even fit your toilet?

You should definitely know the answer to this before ordering your bidet toilet seat. The excitement for your new bidet would quickly end if it arrived and wasn’t compatible with your toilet. This bidet article explains how you can ensure a bidet seat will fit your toilet.

When researching toilet bidet seats, you may have come across things like, "This bidet will fit all two-piece toilets." But what is a two-piece toilet? When bidet enthusiasts talk about a two-piece toilet, what they mean is that the toilet bowl and water tank are two different pieces. Although they are securely bolted together, you can tell that the toilet bowl and water tank are "two pieces" (which you could actually take apart, if you wanted to).

With one piece toilets on the other hand, there’s no separation between the toilet bowl and water tank. It’s all "one-piece" and seamlessly connected.

Most bidet stores and manufacturers will claim their toilet bidet seats fit all two-piece toilets. It’s harder to make such a statement about one-piece toilets though, because they’re harder to fit. Why? Because for a bidet to fit, there has to be enough clearance between the front of the water tank and the back of the toilet bowl. This can be a challenge with one-piece toilets, or toilets where the water tank’s curvature restricts the space where the rear of the bidet resides.

To make things easier, we’ll give you a rule to follow when determining if a bidet toilet seat will fit your toilet. And this rule true holds regardless of whether you have a one-piece or two-piece toilet. Here’s the rule: just in front of your water tank, there are two mounting holes which secure the toilet seat to the toilet. Measure the distance from the front of the water tank, to the center of these two holes. You’ll need to take into account any curvature in your water tank, so measure from the point of the water tank that is nearest to the mounting holes. Verify there’s at least 1.5 inches (or more) of clearance all the way across the back. If you answered yes, then congratulations. A bidet toilet seat will fit your toilet.

But what if you have less than 1.5 inches of clearance on your toilet? That’s okay too, but your bidet options become more limited. If this describes your situation, we suggest you check out the Coway BA-13 bidet (Coway is a manufacturer of bidet seats). These seats have been specifically designed to fit one-piece toilets.

Once you’ve determined that the toilet bidet seat will fit, next we’ll need to figure out if you need an elongated seat or round seat. Take one more measurement from the center of the mounting holes to the very front of the toilet bowl. If it’s 17.5 inches or more, you should order a bidet with an elongated seat. If it’s 17 inches or less, you’ll want a round seat.

In summary, it’s very important to make sure the bidet seat will fit your toilet prior to ordering. Make sure there’s at least 1.5 inches (or more) of clearance between the front of the water tank and the center of the mounting holes. If your water tank is curved, measure from the point of the water tank that is nearest to the mounting holes. To determine if you need an elongated seat or round seat, measure from the mounting holes to the front of the toilet bowl. A measurement of 17.5 inches or more indicates you’ll need an elongated seat, while 17 inches or less means you should order a round seat.