There will come a time when you have to replace your toilet seat completely, either because it’s broken or because of wear and tear. And in order to avoid buying the wrong product, you need to know the size of your toilet seat. But are there different toilet seat sizes, or is there a universal standard that fits every toilet?

This article will aim to answer that question, but I’ll go the extra mile and dig a little deeper. In addition to sizes, I’ll also cover the various materials and shapes of the seat you need to replace, as well as proper ways of measuring toilets in order to find the perfect alternative.

Various Toilet Seat Shapes 

You will be forgiven if you assume that there’s only one shape of toilet seats, or rather just one shape of toilets in general. After all, each country has its own standards when it comes to toilets. However, if you pay close attention to the bathrooms all around you (at your friend’s or your relative’s house, at the mall, at your place of work, in the hospital, etc.), you’ll see just how much variety there is to seat shapes. So, let’s cover some of the most common ones.

Oval Seats

Oval or elongated seats are pretty much the standard of every American home. You will recognize them anywhere with their elongated, pointy ‘nose’, which is about 18 inches away from the toilet bowl’s mounting hole. The manufacturers specifically chose this shape because of its sanitary benefits and relatively easy maintenance.

Round Seats

Round seats are just as common as oval ones, which means you’re likely to find a replacement incredibly easily. The only real difference between these two common types is the shape and the size. A typical round seat will measure around 16 inches between the mounting hole and the tip. It’s just enough space to allow you to relieve yourself without feeling cramped or tight.

Square Seats

Unlike the previous two, square seats are more common in Europe, especially the UK. You can usually find these seats in huge shopping malls and other public areas, but they have become increasingly popular in regular British homes in the past several decades. Their most unique feature is the titular square shape, which allows for a lot of space between the legs, but might not leave a lot of room for the genitalia while you sit.

D-Shaped Seats

A typical D-shaped seat combines the best of the three shapes mentioned above. It has a rounded tip, just like the oval and round seats, but most of the rim is square, allowing you more stability while you sit. Similarly to square seats, this option is quite common in Europe.

Open Seats

This seat type has a small opening at the front, making it resemble a ‘U’ shape. These seats are the standard legal requirement in the US public restrooms. Not only do they provide more room for wiping without you touching the bowl or the seat, but they also protect the toilet from any urine dripping when men urinate.

Original vs Dedicated Seats

While googling, you must have run into the terms ‘original’ and ‘dedicated’ and read countless articles describing what they are and how they’re different. Let me sum those up in the quickest way possible: an original seat is a seat designed by the toilet bowl manufacturer, such as Kohler. In other words, the seat is tailor-made for the bowl right down to the tiniest measurements. A dedicated seat, on the other hand, is made by third-party manufacturers and you can fit it on various different bowls.

If possible, always try to get the original seat. However, if the bowl you’re using comes from a manufacturer that no longer exists, make sure to buy the highest quality dedicated seat you can find.

Toilet Seat Materials

Aside from different shapes, toilet seats also come in various materials. The following is a brief overview of the popular materials and what their benefits are.

Wooden Seats

Getting a wooden seat would make your bathroom stand out. With a nice, polished finish, this type of seat is not only stunning but quite comfortable as well. Most people pick either bamboo or medium-density fiberboard, but no matter the option, you’ll be pleased with the result.

However, there is a downside to using wooden seats. Moisture can warp the wood in unnatural ways, so it can either rot on the inside or snap and break. In addition, some seat cleaners can damage the surface.

Plastic Seats

By far the most common option, plastic seats are cheap, easy to replace, and quite easy to clean. Sadly, they are not perfect. Constant exposure to cold weather can cause these seats to snap in two. On the other hand, extreme sunlight can cause its colors to fade.

Polyresin Seats

Polyresin seats are lighter than most wooden or plastic seats, but they are by far the most fun option on the market. You can quite literally choose any design for the seat. For example, it can have a see-through cover with fish swimming or boats floating on the waves. The only real downside to a polyresin seat is that it tends to be expensive when compared to other variants.

Are All Toilet Seats the Same Size?

Thus far, I didn’t mention any particular sizes of toilet seats. The article has focused mostly on shapes and materials, and it has even covered what dedicated toilet seats are. So, how come there are no raw numbers yet, or a clear answer? Is there a standard size for toilet seats or not?

Well, the simple and obvious answer would be No. However, I wanted to illustrate WHY exactly that’s the case. As you can see, the shapes of the seats alone will tell you that there’s no one-size-fits-all seat out there. But even if we were to take just one type, e.g. oval seats, we would still not have a single, universal size.

For that reason, it’s highly important that you know how to measure your toilet seat in order to get the exact seat you need. That way you can avoid wasting money on products that claim to be ‘a one-size-fits-all seat for every home.’

How to Measure Your Toilet Seat

The first part you’ll need to measure is the distance between the two fixing or mounting holes. Out of all the elements you will be measuring, this is the only one that has a certain ‘universal’ size. That size should be around 155 mm or 6.1 inches.

Next, you need to measure the width of your bowl. Take your tape measure and place it between the points where your bowl is the widest.

Finally, you’ll need to figure out the depth of your bowl. In order to do that, place one end of the tape measure at the top of the bowl. The other end should go exactly between the two mounting holes.

Once you have these measurements in mind, you can find the best toilet seat that fits your needs.

Some Other Toilet Seat Options

  • If you happen to have some disability or have an elderly family member, consider getting a raised toilet seat. They’re also an excellent option for extremely tall people who have trouble sitting down.
  • Heated toilet seats have also become extremely popular, especially in areas with lots of cold weather.  If you have some money to spare, get yourself one of these seats. That way, you can reduce the risk of catching a cold by sitting on ice-cold plastic.
  • Sometimes, you or your loved ones can slam the seat down and cause a lot of noise. In order to prevent this, get a soft-closing seat and save yourself some trouble in the future.


As stated, there is no universal size when it comes to toilet seats. With so many different shapes and materials out there, it’s impossible to get a product that can work with every bowl.

Hopefully, this article will help you in figuring out the exact size of your seat so you can easily replace it in the future, if the need ever arises.

You might also want to read: How to Fix a Toilet Seat That Keeps Falling

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