Toilet Seat Sizes: Major Types, Measurements, and Selection

Buying a toilet seat doesn’t require careful consideration. Or does it? Many people believe that toilet seats come in one universal size. However, this couldn’t be farther from the truth. While most seats are designed to fit a standard round or elongated toilet, modern toilets may require a non-standard or even a bespoke seat.

Standard toilet seat sizes are 18.5 by 14 inches for the elongated type and 16.5 by 14 inches for the round toilets. However, some toilets are wider or longer. Thus, you should always measure your toilet before buying any type of toilet seat.

Are Toilet Seats Universal?

The short answer to the question above is no; toilet seats are not universal. However, most toilet seats do have a standard size of either 18.5 x 14 inches or 16.5 x 14 inches. These seats fit the most popular toilet styles, which are elongated and round.

However, modern toilets come in a variety of styles. We can talk about elongated toilets, round toilets, square, angular, and D-shaped. Then, there are the suspended toilets that generally have smaller bowls.

With this in mind, finding the right toilet seat size requires some consideration. In addition to learning how to measure your toilet, you should also check the mounting system and make sure that the seat fits the bowl rim perfectly.

Another thing to keep in mind is that some toilets come with custom-made seats. This is often the case with modern toilets with non-standard sizes or shapes.

If you decide to invest in such a toilet, remember that the only seats that will fit it are custom seats manufactured by the same company. Thus, you may not be able to replace it if the company discontinues the production of your toilet or toilet seat model.

For this reason, you should only buy non-standard toilets that are manufactured by big brand names. Also, make sure that the company manufactures replacement seats for the specific type of toilet that you want to buy. With this in mind, let’s see what the most popular toilet seat styles and sizes are.

Elongated Toilet Seat

Elongated toilets are the most popular type. The oval bowl provides better comfort compared to the round type, mainly thanks to the more generous dimensions. Most elongated toilets on the market have a standard size and are compatible with standard elongated toilet seats.

What are the dimensions of an elongated toilet seat?

Elongated toilet seats measure about 18.5 by 14 inches. This size is nowadays considered standard for most toilets. You can find them in modern residential bathrooms, but also in hotels, airports, restaurants, gas stations, and other businesses.

The main advantage of the elongated seats is the increased comfort. Considering how much time we spend on the toilet each day, many people prefer upgrading the toilets in their home from round to elongated.

Elongated toilets are also preferred because they are easier to use and clean. Moreover, elongated toilets generally have a more forceful flush. The main downside is the higher cost of an elongated toilet. Elongated toilet seats are also more expensive than round seats.

Will the elongated toilet seat fit a standard toilet?

Elongated toilet seats generally fit all standard toilets that have an elongated (or oval) shape. They will not fit a round toilet or another toilet shape.

The toilet seat must fit the toilet bowl’s rim dimensions perfectly, or it won’t provide the expected comfort and stability.

Round Toilet Seat

Round toilets are very similar to the elongated ones but are smaller and have a more traditional appearance. While most people upgraded from round to elongated toilets, the round type still equips smaller bathrooms.

What are the dimensions of a round toilet seat?

Like the toilet, the round toilet seats are slightly smaller than the elongated ones. However, only the toilet’s length changes, most fixtures maintaining the same width. Thus, the standard size of a round toilet seat is 16.5 by 14 inches – which is still oval despite the name.

How do you tell if your toilet seat is round or oval?

You can usually tell if your toilet seat is round or oval by looking at it. Oval seats generally have a more elongated appearance, whereas the round ones appear rounder, despite not being perfectly round.

Another, more certain way to tell what shape your toilet seat has is by measuring it. You can either measure the seat or the toilet rim from the outer side of the rim to the outer side of the seat mounting holes.

As mentioned above, round toilets have a length of approximately 16.5 inches, whereas oval toilets are about 18.5 inches long.

What are Non-Standard Toilet Seats?

Non-standard toilet seats are toilet seats that can have any size or shape. They are found on new, modern toilets, including freestanding and wall-mounted models. Shapes include round, oval, square, angular, and D-shape. Here are a few factors to consider when choosing a toilet seat.

How to Choose a Toilet Seat: 6 Factors to Consider

Toilet Shape

The shape of your toilet is the first thing to consider when looking for a replacement seat. As mentioned above, shapes can vary from round or elongated to square, angular, or D-shape. From all, angular toilets are perhaps the most challenging because their actual shape and size can vary widely.

Angular toilets are toilets designed to fit in the corner of a bathroom and provide a practical solution to those living in small spaces.

The bowl of an angular toilet is generally round or elongated in shape but often smaller than a standard round or oval bowl. Thus, most angular toilets come with custom-made seats.

Toilet Size

Until not long ago, toilets used to have the two standard sizes we mentioned above. Things aren’t that simple anymore, though. Modern toilets come in a variety of sizes.

Round and elongated toilets still adhere to the standard sizes. However, smaller models are also available for apartments with small bathrooms or for half-bathrooms.

Most square toilets also have a standard size, although it is different from the round and elongated – and this toilet type would require a different toilet seat shape. The only way to know for sure what toilet seat size you need is by measuring the toilet.

Toilet Pan Shape

The toilet pan is the part of the toilet that sits on the floor, and you might think it has nothing to do with the toilet seat sizing. However, some pan types have the cistern attached to them, a feature that might change the size of the toilet seat you need.

Type of Hinges 

Regardless of the size and shape, you should also pay attention to the hinges when choosing the right toilet seat. There are two main hinge types, and your toilet will determine which one is suitable for you.

Top-fixing toilet seats with pans that are not accessible from the bottom (such as back-to-wall or one-piece toilets) come with two bolts that you have to feed into the pan. Measure the hole size to make sure the bolts have the right dimension when buying.

If your toilet’s pan is accessible from the bottom, you can install the seat with bolts tightened from underneath. Since these bolts are easy to access, this toilet type makes it easier to replace the seat as often as needed.

Apart from the hinge style, you can also consider whether you’d like a seat with soft-close hinges (the seat won’t bang down if you drop it while closing, making it a safe choice for households with children) or quick-release hinges that don’t require any complicated fastening and unfastening.

Most toilet seats nowadays come with soft-close hinges as standard, but it’s worth checking before buying if this feature is important to you.

Toilet Seat Style

Toilet seats come in a variety of styles, including hard and soft toilet seats. As the name suggests, hard seats feature a hard surface that is very easy to clean. Soft toilet seats are generally padded and then covered with an impermeable material.

These seats are also easy to clean but not as hygienic as a hard seat. Moreover, the upper material is easy to tear apart.

Tech toilet seats are also an option for those who want to sit on a heated seat when using the bathroom or who appreciate LED lighting all around their toilet.


Toilet seats can be made of a variety of materials, including wood, plastic, PVC, resin, or even stainless steel.

Wooden seats are a traditional choice and fit well in classic or rustic interiors. The wood is treated with a waterproof coating, and these seats are available in a number of colors.

Plastic seats are a more affordable – although not as durable – option. Cheaper seats are made of flimsy plastic that can crack or break under your weight. However, higher-quality models are fairly durable and very easy to maintain. Like wood, plastic seats come in a variety of colors.

Synthetic resin seats are very durable and scratch-resistant. They come in solid colors, or you could choose a seat made of transparent resin and featuring decorative details. Resin seats also feel warmer to the touch compared to all other types.


Last but not least, also consider the seat color. You can either choose it based on the color of your toilet or in a contrasting hue. Popular options include black or dark brown seats in a traditional or country-chic bathroom.

Alternatively, you could match the seat color to the color of your tiles or wall paint. This allows you to add a splash of color to your bathroom.

How to Measure a Toilet Seat for Replacement: 3 Easy Steps

Measuring the toilet seat for replacement is child’s play. All you need is a tape measure, as well as paper and a pencil to write down the numbers.

1. Determine the midpoint between the mounting holes

For an accurate measurement of your toilet seat, you must determine the distance from the tip of the toilet rim to the outer side of the mounting holes. To do that, you have to determine the midpoint between the mounting holes.

Grab the tape measure and determine the distance from the middle of one mounting hole to the middle of the other mounting hole (this is 5-1/2 inches for most toilets). Divide the number by two – you’ll end up with a midpoint of about 2-3/4 inches.

2. Determine the toilet seat length

Measure the distance from the midpoint at the back of the toilet to the tip of the toilet bowl (the outer rim).

3. Determine the toilet seat width

Measure the width of your toilet from the outer of the rim to the outer of the rim, in the widest point of the bowl (generally around the middle). This is the toilet seat size you should buy.

Related Questions

Measuring and sizing the toilet seat isn’t complicated, but you may still have questions. Check out the answers below.

Are all elongated toilet seats the same size?

Not necessarily. While most elongated toilets have a standard size, there are smaller models designed for smaller bathrooms. It is recommended to measure your toilet before buying a seat.

How often should you replace your toilet seat?

You should replace the toilet seat if it is cracked or if the fasteners are corroded. While there isn’t a general rule, most toilet seats will last for five years or more.

Why do European toilets not have seats?

European toilets, much like American ones, have toilet seats. The main reason you may find seatless toilets in public restrooms is that the seats break, and businesses decide against replacing them. Another reason why some toilets in Europe lack seats is because they came with custom seats that are no longer in production.

Final Thoughts

Most toilets found in American homes are either round or elongated and require a standard size of toilet seat based on their type. Non-standard toilets are rarely used in homes, but you can still find custom toilet seats for most basin shapes. Hopefully, the guide above can help you measure the toilet seat for an accurate replacement.

Recent Posts