How to Measure for a Toilet Seat in 5 Minutes

Last Updated on July 8, 2023 by toilethaven

Are you about to replace your toilet seat but can’t decide on what size of seat to buy? Measuring for a toilet seat is a fairly easy task that should not take you more than five minutes.

So, does it matter what size of toilet seat you buy? Yes, it matters. Toilet seat sizes are not standard.

In the United States, toilet seats, just like bowls, are either round or elongated. You cannot replace a round toilet seat with an elongated seat, nor can you replace an elongated seat with a round one. You could even have a square or D-shaped toilet seat.


To measure for a toilet seat, measure the distance between the center of the 2 seat mounting holes and the front of the bowl, keeping the measuring tape as central as possible. If you get 18.5 inches, you have an elongated seat, but if you get 16.5 inches, you have a round seat.

The best way to tell your toilet seat size is by measuring the length of the bowl. It is around 18.5 inches for an elongated seat and 16.5 inches for a round one. The shape of the bowl can also guide you—an oval for elongated seats and a circle for round seats.

There are 2 main toilet seat sizes in the United States, elongated seats (18.5 inches) and round seats (16.5 inches). However, you can get square or D-shaped toilet seats in other countries like Europe and some American homes.

It is important to ensure that the measuring tape is as central as possible on the toilet bowl in order to get a correct figure. Apart from the length, you should also measure the bowl’s width and bolt spread.

Therefore, the size of a toilet seat depends on the type of toilet you have (round vs elongated.) That is why we measure the size of the toilet bowl and not the actual seat you are replacing.

Elongated toilet bowls and seats have a bigger surface area than round toilet bowls and seats. In fact, some people don’t even need to measure them to tell them apart.

I have written a detailed article on the best elongated and round toilet seats. Read it here.

3 Ways of Measuring For a Toilet Seat

  1. Toilet seat length
  2. Toilet seat width
  3. The toilet seat bolt spread

Let us look at each one of them in detail.

1. How to Measure a Toilet Seat Length


To measure a toilet seat’s length, you must remove the toilet seat. This is because you must measure the bowl, not the seat itself. I have included a section on how to remove a toilet seat further below. When your toilet seat is off, proceed as follows:

  • Locate the 2 toilet seat mounting holes on the toilet bowl.
  • Once you have located the mounting holes, estimate the center point between the holes.
  • Place the tip of the measuring tape at the center of the two holes and stretch it out to the frontmost point of the bowl rim.
  • Write down your measurement.

If your measurement is around or exactly 16.5 inches, you have a round-front bowl and need to order a round-front toilet seat.

A measurement of exactly or around 18.5 inches means you have an elongated toilet bowl. You will therefore need to buy an elongated toilet seat.

These days toilet manufacturers are making what are called compacted elongated toilets. Don’t make the mistake of thinking that there are compact elongated toilet seats. The toilets as a whole are compact, but not the bowls.

2. How to Measure a Toilet Seat Width


The width of a toilet seat is measured from the middle of the toilet bowl, which happens to be the widest part of the bowl.

An excellent trick is to imagine your toilet seat as a wall clock while standing in front of the bowl. When you already have that picture in mind, you must measure the distance between the 9 to the 3 o’clock mark.

Write down your measurements. The dimensions differ between the United States and other regions like Europe, where it is common to find D-shaped toilet seats. The width of toilet seats in the US is generally between 14 and 14.5 inches.

3. How To Measure a Toilet Seat’s Bolts Spread


The bolts spread is the distance between the 2 toilet seat bolt holes. You will need to remove your toilet seat to measure the bolts spread.

In the United States, the bolt spread is a constant 5.5 inches. The bolt spread in Europe is between 6 and 6.5 inches. Some toilet seats are designed to accommodate a range of bolt spreads instead of a fixed one.

Example of Each of The Two Types of Toilet Seats

1. Round toilets seats

Round toilet seats have been around for a long time and are the most common seats in older houses. They are also referred to as standard toilet seats. The front of these toilets is semicircular (round) and hence the name round-front toilet seats.

2. Elongated toilet seats

Elongated toilet seats are quite modern, just like elongated toilets, and are preferred by most people. They are oval-shaped and longer than round toilets and, therefore, more comfortable.

It is important to note that elongated toilet seats can only be installed on elongated toilet bowls, and the same for round toilet seats. This is why measuring a toilet seat before buying is important.

How to Remove a Toilet Seat

If you need to measure a toilet seat correctly, you may need to remove the toilet seat. It is a simple task requiring only a flathead screwdriver and an adjustable wrench (optional). Proceed as follows:

  • Locate the toilet seat bolts. These 2 bolts are found at the back of the toilet seats and are usually concealed by plastic caps.
  • Pry the plastic caps off with the screwdriver. From there, you can see the bolt heads.
  • Reach for the underside of the toilet bowl to locate the wingnuts used to tighten the bolts. Nuts are found in bottom fixing type of toilet seats. Top-fixing toilet seats do not require nuts.
  • Hold the wingnut with one hand (left hand if you are right-handed) and use your other hand to loosen the bolt with a screwdriver.
  • If the nuts are regular nuts without a wing, you can use a wrench to back them off if they are too tight.
  • Unscrew both bolts and lift off the toilet seat.

Plastic vs. Wooden Toilet seats.

After measuring your toilet seat, you must decide on the material you want your next seat to be made of.

Toilet seats are either made of plastic or wood. Plastic toilet seats are more common than wood and are cheaper and long-lasting. Read more on the pros and cons of plastic vs. wooden toilet seats in this post.

Wooden toilet seats are warmer and more comfortable than plastic toilet seats. People who buy wooden toilet seats say they are more stylish than plastic ones.

How to Choose the Best Toilet Seat

When choosing the best toilet seat to replace your old one, you will need to compare quite a couple of variables. Let us have a look.

Top Fixing Toilet Seat

Top-fixing toilet seats will allow you to install your toilet seat from the bowl’s top part. You will not need to bend to tighten the nuts under the bowl. This is a great choice, especially if you have a painful or weak back.

Bottom Fixing Toilet Seat

Bottom-fixing toilet seats are the opposite of top-fixing toilet seats. These toilet seats must be tightened from the bowl’s top and bottom.

Soft Close Toilets Seat

Soft close toilet seats are beneficial if you hate the sound of a toilet seat slamming on the bowl. The toilet seat and lid close slowly and settle on the bowl without a sound. They are also known as slow-close or quiet-close toilet seats. Check out some of the best soft-close toilet seats in this post.

Quick-Release Toilet Seat

A quick-release toilet seat is designed to simplify your life, especially when cleaning the toilet. They can be attached and reattached easily on the toilet seat mounting hardware, allowing easy and fast cleaning.

Raised Toilet seats/ Toilet Seat Risers

Raised toilet seats are installed with standard toilet seats or on the toilet bowl to add height to the toilet. They are the best choice for the elderly, disabled, and recovering from knee or hip surgery.

Most toilet seat risers are between 2 and 6 inches. Padded and toilet seat risers with arms are some of the best to buy.

Heated toilet seats

With a heated toilet seat, you will surely spend more time in the bathroom. Heated toilet seats combine other features such as soft-close, quick-release, and nightlight. A great example of such is the Brondell LumaWarm toilet seat.

Nightlight Toilet Seat

A toilet seat with a nightlight usually is illuminated at night, mostly with a blue light. Most nightlight toilet seats are also heated, soft-close, and quick-release.

Would you like a heated toilet seat? Check out this review of one of the best-heated toilet seats.

Bidet Toilet Seat

Bidet toilet seats go the extra mile of cleaning your posterior and front after doing your business on the toilet. It also dries you with warm air, among other luxury functions.

I have written a detailed review of the best bidet toilet seats in the market. Read it here.

How to Measure for a Raised Toilet Seat

  • Have the person you intend to use the raised toilet seat stand on their feet if possible.
  • Measure the distance between the floor and the top of their thigh, just behind the knee.
  • Now measure the distance between the floor and the top of the existing toilet seat.
  • Subtract the second measurement from the first measurement.
  • Order a raised toilet seat with that measurement.

Most Popular Toilet Seat Brands

  1. Bemis toilet seats
  2. Mayfair toilet seats
  3. Church toilet seats
  4. Bath Royale toilets seats
  5. American Standard toilet seats
  6. Kohler toilets seats
  7. Toto toilet seats