Toilet Dimensions (Standard, Rough-in Distance and Common Sizes)

Toilets are essential fixtures in every bathroom, consisting of a bowl, tank, seat, and seat cover. The evolution of toilet brands and types of toilets has seen a transition from simple pit latrines and chemical toilets to sophisticated water cisterns and even smart toilets.

Present-day toilets offer various bowl designs, seat styles, and even technological enhancements for an improved user experience. Among the most popular toilet designs are one-piece, two-piece, and wall-hung models. Understanding toilet dimensions is crucial when selecting the right toilet for a bathroom to ensure the best fit and function.

This article delves into toilet dimensions, providing insights into measuring a toilet, toilet bowl shapes, essential factors to consider when buying a new toilet, and the basics of installation. By gaining a comprehensive understanding of toilet sizes, you can ensure that you find a suitable, well-fitting, and comfortable toilet for your bathroom.

Here is a quick sum-up if you are short on time.

  • Standard Toilet Dimensions: Typically range between 27-30 inches in depth, around 20 inches in width, and between 27-32 inches in height. The rough-in is usually 10-12 inches.
  • ADA Compliance: For a toilet to be ADA compliant, its seat height should be between 17” and 19”.
  • Toilet Rough-in Dimensions: Describes the distance from the back wall to the drainpipe’s center. Standard is typically 12 inches.

What are the Dimensions of a Standard Toilet?

Toilet Sizes

Standard toilet sizes are usually between 27 to 30 inches deep, that is, 69 to 76 cm, about 20 inches in width, i.e., 51 cm, between 27 to 32 inches in height (68.5 cm to 81 cm), and feature a rough-in of anywhere from 10-12”. You won’t want to have a large toilet in a tiny bathroom, so the dimensions of your toilet are important.

You’ll also not want a toilet that’s so big that people using the toilet constantly run into the wall when trying to move about around the toilet or one that’s so broad that it lays too tight beside the shower or bathroom.

If you prefer a taller toilet, you have to ensure that it complements other components of the bathroom – if it’s a lot taller than the sink, for instance, then it can appear unfitting. You also would not like to buy a toilet so small that it makes other parts of your bathroom furnishings and accessories look weird.

Furthermore, if your toilet is too tall, you’ll end up being very uncomfortable and on your toes when sitting on it. Likewise, if it’s too small, you may have to squat. For this reason, there are several options for toilet dimensions with varying quality setups. One of these includes:

ADA Compliant Toilet Seat Height

ADA compliant toilet seats

To be ADA compliant, the distance from the floor to the peak of the toilet seat should be between 17” and 19”. This is about 43.1-48.3 cm. Note that this distance is measured to the top of the toilet seat and not to the rim of the toilet bowl.

Until recent times, standard toilets were about 15 inches long, that’s about 38.1 cm. This was a few inches shorter than ADA accessibility requirements. You usually find the new standard height in most comfort height toilets nowadays.

Toilet Rough-in Dimensions

Toilet rough-in distance

The rough-in measurement of a toilet describes the distance from the back wall to the middle of the drainpipe at the bottom of a standard toilet. The rough-in measurement of a regular toilet design is usually 12 inches, which is 30.5 cm.

How to Measure a Toilet

A very important step to take when buying a new toilet is to first make sure that it suits your space. To get the appropriate size toilet, take a measuring tape and get these essential measurements:

Toilet Depth

Start from the front of the toilet bowl to the end of your tank. It’s recommended that you leave a minimum space of 24 inches in front of the toilet. This guarantees that there will be enough space to walk around in front of your toilet and that your bathroom door won’t keep hitting the toilet, assuming the toilet is situated beside the door.

Toilet Height

Start from the ground to the top of your toilet rim. Make sure that your toilet that would be at a height at which it’s easy for you to sit and stand.

If there are any storage racks or other installations above your toilet, then you also have to measure the distance from the ground to the top of your toilet’s tank to ensure that your new toilet will accommodate that exact space and that you can sit comfortably on it without having your head hit any obstructions above the toilet.

Toilet Breadth

Start from the left corner to the right corner of the toilet rim (the widest part of the rim). Your toilet needs to have a minimum space of 30 inches, regardless of its location within your bathhouse.


The most important dimension to measure when buying a new toilet is the Rough-In; this is the space from the middle of the toilet’s floor drain to the finished wall. To take this measurement, grab a measuring tape and check from the rear wall to the middle of the waste outlet.

The common toilet dimensions for rough-ins are 12,” but in a few cases, especially in older homes, it might be a little bit longer or shorter than 12”.

Toilet Bowl Shapes and Their Dimensions

The toilet has two bowl shapes, namely, round and elongated bowls.

Round Bowl Shapes

Round bowl shapes have a circular design, and they take up less space. This means that they are the best fit when space conservation is of utmost importance.

Elongated Bown Shapes

Elongated bowl shapes have a pear-shaped design, and this bowl type provides more comfort and is usually 2 to 3” lengthier than the first bowl type.

Some Common Types of Toilets and Their Dimensions

Back-to-Wall 1 Piece Toilet

Back to wall 1 piece toilet

This traditional and simple toilet with one piece makes a compact choice for small bathrooms. Also, a 1-piece toilet offers a sleek design and tends to be more efficient and long-lasting as they are just composed of fewer components.

Some model, like the TOTO Aimes One-Piece Toilet, has a product with roughly 16″ in width and 28.5″ in depth. Its toilet tank height is 28″, and the seat is 17″ high.

Back-to-Wall Long 2-piece Toilet

Back to wall long 2 piece toilet sizes

If you have a huge bath or tall family members, then consider buying toilets with dimensions similar to a Back-to-Wall Elongated 2-piece. From the wall to the front end of your toilet bowl, the Back-to-Wall Elongated 2-piece measures 30.5” – this is appropriate for big baths.

Keep in mind that this toilet would look too big in small bathrooms. The rim of the toilet is 18.5 inches in length and below 14″ in width.

Apart from its elongated nature, Back-to-Wall Elongated 2-piece toilets have a few height advantages as well. The rim is 16.5 inches above the floor. This height permits the majority of average height to tall adult users to sit much easier on the seat.

Also, unlike the majority of close-fitting toilets that feature a tank beneath the toilet bowl, this toilet type permits a long secondary unit at the rear of its toilet bowl. In this design, the tank is 30.75” above the floor.

Wall Hung Toilet

Wall hung toilet

If you need a modern, space-spacing wall-hung toilet is among the best choices. As the name says, the toilet is fixed to the wall and has some distance from the ground, which makes it easy to clean the spaces around it. A typical wall-hung toilet like this Concorde model measures 22 5/8″ in length, 14 3/16″ in width, and 14″ in height.

Toilet Installation Essentials

Choosing the toilet dimensions you prefer is just the first step in getting a toilet. The next thing is finding out how to install the toilet.

Except you stay in a remodeled commercial building or a hand-made cabin that was built before major home zoning regulations, or you just choose to go against the norms when building your condo, you need to create an outflow water pipe in your floor that will remove all waste matter away from your building and into your septic tank or out to the sewer treatment facility in your area.

This outflow hole is the main point of your toilet installation process as it must align perfectly before other aspects can function perfectly.

Things You Should Consider When Buying a Toilet

While shopping for a new toilet, you must take note of the numerous product features that you feel are important. You also need to be aware of other important factors beyond your preferences.

For instance, you have to consider your bathroom layout and select a toilet that suits it. There are particular features, aspects, and characteristics you have to look out for when shopping. They include:

Practical and Aesthetic Features

Do you prefer a functional toilet, or are you more interested in aesthetics? If you are more interested in aesthetics and you’re setting up a contemporary toilet, then you might want to go for a present-day styled skirted toilet for its artistic appeal instead of an ordinary wall-hoisted toilet as the wall-hoisted toilets are not as aesthetically pleasing as the skirted toilets.

On the other hand, if you want a functional toilet, you may want to consider choosing a pressure-aided toilet over a multi-flush toilet as pressure-aided toilets can flush much waste with just a little water.

Toilet Shape

Elongated toilet bowls are more aesthetically pleasing than round ones, so you can choose a long toilet if aesthetics is important to you. Furthermore, contemporary toilets are becoming increasingly sophisticated; you would easily be blown away by the latest toilet features.

Currently, smart toilets are available that warm up your seat, clean up by themselves, and can be tailored to meet the exact dimension of your bathroom if you’re willing to pay the price for them.