Are Toilet Seats Universal? Standard Sizes You Need to Know

are toilet seats standard sizes

There are so many options when it comes to buying toilet seats that you might want to just buy the first one you see and get out of there. But, I think I can save you some time and hassle. The first thing you really need to know, is the answer to this question: are toilet seats universal sizes?

There are two standard sizes of toilet seats in the United States. They are elongated and round. Elongated toilet seats are 18.5 inches long and round toilet seats are 16.5 inches long. To find out what kind of toilet seat you need, measure from the end of the bowl to the middle of the seat post holes

If this all sounds like jargon, don’t worry. In the next couple of sections, I’ll show you the differences between the two, and how you can properly measure the size you need for your toilet seat.

  1. Are Toilet Seats Universal?
  2. How to Measure Your Toilet Seat
  3. Non-Standard Toilet Seats
  4. Related Questions

Are Toilet Seats Universal?

elongate v round toilet seat

Before we dive into the two main standard sizes of toilet seats, there’s a couple of overall toilet standards that you should know.

First, the distance between the two bolts that hold your toilet seat to your toilet bowl is standard across nearly all toilets, regardless of what kind of shape it has. These are called seat post holes and they should be about 5.5 inches apart from the center of one hole to the other.

Second, the width of the toilet bowl is usually the same regardless of shape as well. If the width does vary, it’s usually only by less than half an inch.

Now that we’ve got those things covered, let’s dig into the different types of toilet seats.

Elongated Toilet Seat

Elongated toilet seats measure about 18.5 inches long and about 14 inches wide.

Elongated toilet seats are preferred by many, especially men, because of their extended size. Because of its popularity, this is the seat that is standard in most large businesses such as hotels, gas stations, and airports.

Although they’re more common in large businesses, you can also find them in houses and apartments.

Round Toilet Seat

First off, the measurements. Round toilet seats measure about 16.5 inches long and about 14 inches wide.

In general, round toilet seats are more common in homes and houses. They are also used more often in smaller bathrooms because they take up less space than their elongated counterparts.

Also, because round toilet seats are a couple of inches smaller than elongated seats, they tend to be on the cheaper side, but not by much.

How to Measure Your Toilet Seat

how do i measure my toilet seat

Now that you know about the standard sizes, you probably want to know how to figure out what size of toilet seat you have.

To make sure you get all the measurements you need before you go to the hardware store, measure these 3 things:

  1. Length
  2. Width
  3. Seat post holes

Let’s get to it.

1. Length

This is by far the most important measurement. The other two are usually standard so if you don’t want to hassle with remembering three different numbers, just get this one.

But, I’d advise you to measure the other two just to make sure you have a standard-sized seat.

To get this measurement, measure from in between the seat post holes to the end of your bowl. Make sure you measure to the outside edge of your toilet bowl, otherwise you’ll end up getting a shorter measurement than you need.

Here’s a picture for all you visual learners out there.

Measuring toilet seat length

This will determine if you have an elongated bowl or round bowl. Just to review, elongated bowls will be around 18.5 inches, like the one I’m measuring in the photo above, and round bowls will be about 16.5 inches.

2. Width

Like I said earlier, the width is usually standard, but just to make sure you don’t have a really weird sized toilet, take this measurement anyways.

To get this measurement, just measure across the widest part of your toilet bowl. Again, make sure you’re measuring from outside edge to outside edge. Here’s another picture to illustrate.

Measuring toilet seat width

If you do get a measurement that’s different than the typical 14 inches, then you may have a non-standard toilet seat which I talk about in the next section.

3. Seat Post Holes

Lastly, you’ll want to measure your seat post holes to ensure your toilet is a standard size.

For this measurement, measure from the center of one seat post hole to the center of the other.

If you don’t have your toilet seat off, don’t worry, just try to line up your measuring tool to the center as best you can. Here’s a picture to show you what I mean, I didn’t take my seat off.

How to measure seat post holes

Your seat post holes should measure 5.5 inches, and, if they do, all standard toilet seats will fit your seat post holes regardless of shape.

Non-Standard Toilet Seats

european toilet seats

So, you’ve gone through all the steps and measured your toilet seat only to find out that it’s not a standard size. Now what?

Not to worry, you can still replace your toilet seat if you need to. It just might be a little harder to find the right seat. But first, let’s figure out what a non-standard toilet seat is and why you might have one.

What Is a Non-Standard Toilet Seat?

A non-standard toilet is anything apart from the standard sizes listed earlier in this article. Surprising, I know.

They could be an odd shape, length, or have seat post holes that are farther apart or closer together than the standard 5.5 inches.

If you have different sized seat post holes, you can get replacement hinges for a toilet seat which will match the different sizes of the seat post holes. This also might be cheaper than buying a special toilet seat.

However, buying new hinges won’t fix every situation. Sometimes, you’ll have to buy a specially made toilet seat. The kind of seat depends on who the manufacturer is for your toilet.

Proprietary or OEM Seats

You’re probably wondering, ‘why are there toilet seats that aren’t the standard size?’

Manufacturers are constantly trying out new styles and designs in order to stay competitive and innovative. So, they sell small amounts of these new styles and shapes of toilets to see if they have potential in the market.

These types of seats have two names. They are either called proprietary seats or Original Equipment Manufacturer (OEM) seats.

In either case, replacements for this type of seat can often be hard to find and expensive to replace.

But, not all hope is lost, a lot of specialized plumbing stores and DIY stores sell odd-shaped toilet seats at a cheaper price than buying it straight from the manufacturer.

How To Know What Type of Seat To Get

If you have a non-standard sized toilet seat and you need a replacement, you first need to figure out who the manufacturer is of your toilet.

Most toilets have a logo or the name of the manufacturer in between the seat post holes. If your toilet doesn’t have that, take off your toilet tank lid and check for a manufacturer’s label. This will be more common if you have a proprietary or OEM toilet.

If all you can find is the logo in between the seat posts, that’s alright. Take measurements of your toilet and do one of two things. You can search online for places that sell your sized seat, or you can take it to your local hardware store and see if they can help you out.

If you find a manufacturer’s label under your toilet tank lid, you should be able to search the manufacturer’s website for replacement parts.

If you want the cheaper option, check the manufacturer’s website to get the name of your specialized toilet. Then search specialized plumbing stores to find an alternative. Putting it into a search engine should give you lots of options.

European Toilet Seat

Another possibility if you have a non-standard seat is that you have a European toilet seat.

European seats have two styles similar to elongated and round seats, but they also have a D-shaped seat that is pretty common.

Luckily, you can pretty easily buy this D-shaped toilet seat online and have it shipped to you. Make sure you measure thoroughly before you make a purchase to ensure you’re getting the size you need.

How do you know what size toilet to buy?

To determine the toilet size you need, you first need the rough-in measurement. This is from the middle of your toilet drain pipe to your wall. If you have limited space, make sure you also measure the width and length of the area that you want your toilet to fit in.

How do you replace a toilet seat?

To replace a toilet seat, begin by removing the old seat by unscrewing the seat posts. You may have to use a wrench if the bolts are rusted. Installing the new seat depends on what type of seat you have. You should check the installation instructions or the manufacturer’s website to ensure you follow the proper steps.

Matt & Heather

Welcome to our blog! We have a home, but not much time. So our goal is to make big improvements with limited time and money. If you're in the same boat, check out more of our stuff, and join the conversation!

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