Can I Put A Bigger Toilet Seat on a Round Toilet?

Round toilet seats are more commonly seen in houses and homes than their elongate counterparts. They are also ideal for smaller bathrooms because they take up less space, but can your round toilet seat be too small?

Since toilet seats come in different shapes, you may end up with one too small for you if you don’t pay attention during selection. Round toilet seats are typically 16-17 inches long and 13 to 15 inches wide.

Ensuring your round toilet seat fits you for maximum comfort is essential. 

Can I Put a Bigger Toilet Seat on a Round Toilet

Technically, an elongated toilet seat can fit on a round toilet, but you won’t achieve the perfect comfort and fit. Such a seat will likely cause an overhang on a round toilet, which won’t pose an issue for the most part unless the toilet rim shows within the toilet seat opening. 

In that case, individuals, especially males, may feel uncomfortable using the toilet. You can determine if putting an elongated toilet seat on your round toilet will create an overhang by measuring the seat’s opening. 

Do Round Toilet Seats Come in Different Sizes

Round toilet seats are available in various dimensions and sizes, measuring about 16-17 inches long and 13 to 15 inches wide. Therefore, it’s important to precisely measure your toilet to ensure the round toilet seat you get isn’t too small or bigger. 

Don’t approximate the width, length, and distance between the seat post holes if you want to have a seat that perfectly fits your toilet. 

Do All Round Toilet Seats Fit the Same

A standard round toilet seat measures about 16.5 inches long, shorter than its elongated counterpart, which is about 18.5 inches. You will find a round toilet seat in an oval or round shape.

It becomes easier to find the appropriate toilet seat once you know the length of your toilet bowl. Get a round toilet seat if you have a 16-17 inches long toilet.

Since the shape rather than the precise measurement determines how toilet seats are sold, it is more helpful to know whether it’s elongated or round.

See also Why is there Urine under the Toilet Seat?

How Do You Measure A Round Toilet Seat

So, you want to replace the toilet seat on your round toilet, seeing that it’s too small, but you don’t know the correct size? Worry not; you can determine the size of your round toilet seat easily following simple steps.

 You will need to measure:

  • The length
  • The width 
  • The seat post holes

Below is what you need to do to replace your round toilet seat.

Determine The Toilet Type You Have

Toilets serve the same purpose but come in different designs and styles, including:

  • Rectangular or square-shaped toilets
  • Speciality toilets for people with disability, elders, and kids
  • Tankless wall-mounted toilets
  • Standard sized oval or round toilets
  • Bidets
  • Oval toilets with u-shaped/ inverted seats

The size of your toilet directly influences the measurement of the toilet seat. Toilet sizing in Europe and the United States varies. 

Remove The Toilet Seat

Removing the toilet seat, whether your toilet is centrally positioned or placed at the corner,  eases the work of measuring the toilet seat. Before pulling off the lid, wear gloves and remove the bolts and clips.

Having the toilet surface totally bare give you complete access to measure it. Knowing the size of the toilet cover may come in handy, so measure the widest and longest points after flipping it over.

Clean The Toilet

Clean the toilet to remove any splash-back and germs. Disinfect the bare seat, wipe the toilet rims and sides, and any part you will likely touch, including the removed toilet seat cover. 

Measure the Width

This involves measuring how wide the toilet is, and while toilets come with a standard width, it is vital to be sure. Therefore, take the measurement across the toilet bowl’s widest part using a tape measure, ensuring it is from one outer edge to the other, and note down the measurement.

If your toilet seat is standard, it will measure about 13 to 15 inches, although round toilet bowls may be a bit wider. On the other hand, elongated seats tend to be narrower by approximately one or two inches.  

Measure The Length

You will want to pay great attention to it because while the width and the seat post holes are typically standard, the length will likely vary. Determine the distance between the outside edge of the toilet bowl and the seat post holes to find out your toilet seat’s length.

Make sure you stretch your tape measure to the outside edge of the toilet bowl rather than the inner edge to avoid getting a shorter measurement. 

This measurement will also tell you if your toilet seat is round or elongated. Elongated toilet seats have a more extended outside edge (18-19 inches) than round ones (16-17 inches).

Measure The Seat Mounting Holes

This entails measuring the distance between the mounting holes of the toilet bowl at the back. Do so by placing a ruler next to each hole, then note the distance between them, ensuring you register the furthest gap. 

Every standard toilet seat, regardless of shape, should be compatible with your toilet if the distance between the seat post holes is 5.5 inches. 

Make sure you write down all the measurements you get.

See also How To Fix Cracked Toilet Seats

Measure The Wall Gap

Finding out the size of the wall gap comes in handy if you have a speciality toilet, D-shaped toilet, and tankless toilet. Place the tape measure in the middle of the bolt holes, then stretch it to the wall if your toilet touches it.

If the toilet does not touch the wall, extend the tape measure to the toilet back trim or cistern. The wall gap measurement affects the way your toilet seat is attached, ensuring it fits into place perfectly.

Check For Additional Details

Some special toilets like those for the elderly may have extra details like support nobs not found in standard toilets. Moreover, a kiddie toilet may have a seat clamp to ensure your kid can’t open it unsupervised. 

These aspects won’t influence the size of the seat you buy, but they will affect the type. Make sure you note every extra feature your toilet has and even take photos if possible to make the selection for the new toilet seat easier.

See also Why Luxe Bidet Toilet Seat Doesn’t Fit

FAQ On Round Toilet Seat Too Small

Are Round Toilet Seats Smaller?

Round toilet seats are an inch or two shorter than elongated toilet seats, with standard ones measuring about 16.5 inches and 18.5 inches, respectively. However, note that these measurements vary from one brand to the other. 

Are Toilet Seats One Size Fits All

No toilet seats are not one size fits all. Generally there are round and elongated toilet seats in the market. Round toilet seats have a length of about 16.5 inches whereas elongated have a length of 18.5 inches.

How Do I Know Which Toilet Seat will Fit My Toilet

The only way to know the toilet seat size that you will need is to measure your toilet. Measure the width, the length and the distance between the mounting holes at the back of the toilet.


At the very least, your comfort will be affected if your round toilet seat is too small, making using the restroom unpleasant. Fortunately, you can effortlessly solve this problem by replacing the seat with a more fitting one. 

You deserve a comfortable toilet seat, so instead of suffering using an improperly sized seat, make the change and improve your bathroom experience in turn. The measurements you take of the toilet will help you pick the correct seat, so measure accurately and even do it twice to be sure. 

See also How To Replace a Toilet Seat on a Fully Skirted Toto

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