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Toilet Dimensions for 8 Different Toilet Sizes (Toilet Diagrams)

Side profile of a toilet near a wooden screen in a modern bathroom.

Toilet dimensions overview:

  • Height (top of tank): 29″ to 31″
  • Width (tank is usually the widest): 14″ to 16″
  • Height to seat: 16″ to 17″
  • Depth: 28″ to 32″

Note the above can vary considerably depending on the type of toilet.

Related: Toilet Cost | Types of Toilet Flanges | Types of Toilet Seats | Toilet Stores Online | Toilet Brands | Types of Toilets | Parts of a Toilet | Plastic vs. Wood Toilet Seat | How to Install Toilet

The toilet may be a simple household fixture – but it’s one that many of us couldn’t imagine living without. Even simple toilet fixtures can have complicated features. Kick your research off right by checking out this series of basic toilet dimensions, drawings, and definitions.

You might even think that if you’ve seen one toilet, you’ve seen them all, or that the only thing worth deciding upon is whether you want fun and functional features like an integrated bidet, custom seat height or dual-flush capabilities. But pull in those reigns! There is so much more to consider when choosing which throne to add to your throne room.

From a simple corner toilet to a fancy dual flush toilet with a bidet toilet seat – it’s clear that not all toilets are created equal. In light of this, finding the right toilet for your home can be a struggle

Before you head to your local home improvement store or click over to an online retailer, it’s best to prepare yourself for a great array of choices. Toilets come in many different configurations, styles, and features, including features you may have never heard of.

Detailed Toilet Dimensions Diagrams (by type of toilet)

While extra features and components are fun and important, the most important thing to look at is toilet dimensions. After all, you don’t want to get a toilet with an elongated seat if your bathroom is narrow.

You also don’t want a toilet that’s so large that guests hit their knees on the opposite wall when they stand-up, or so wide that it sits too snug next to the bath or shower. If you opt for a taller toilet, you need to make sure it fits in well with the rest of the bathroom – if it’s much higher than the sink, for example, then this could look out of place!

You also don’t want to get a small toilet that makes the rest of your bathroom fixtures and furnishings look comical. A compact toilet is one thing, but an undersized toilet is quite another!

Then there’s the height to consider. Too high and you’re tip-toeing even while sitting and too short and you might as well be squatting.

So how to find the right toilet dimensions? While every person and family is unique, we hope the following look at different toilet dimensions will help you get an idea of quality setups as well as how to set-up those toilets.

Back-to-Wall 1-PC Toilet Dimensions Diagram

Back-to-Wall 1-PC toilet dimensions diagram

If you’re looking for something simple and practical, then you will really appreciate this single-unit toilet. Created as one solitary piece, this compact toilet is a great choice for a small bathroom or apartment bathroom, or for those trying to save space.

You can install the Back-to-Wall 1-PC toilet directly on a finished floor so long as you have the outgoing water pipe available to be installed at 12″ away from the finished wall. There is a 5.5″ gap between the finished wall and the bottom rearmost wall of the toilet. This allows for ample room to reach and clean the water valve for the incoming water to the top of the toilet supply tank. The pipe fitting for the water valve likewise is 5.5″ above the finished floor.

The Back-to-Wall 1-PC’s compact size offers several advantages including being easier to clean, being more durable due to there being fewer shifting components to brake, and having a sleeker, more modern design. This specific unit also comes with the dual-flush option. At the top of the tank, you’ll notice that there is a button for a “Half Flush” and a button for a “Full Flush”. Half flushes use significantly less water and ideal for removing liquid waste while full flushes are powerful enough for the thorough removal of other waste.

Back-to-Wall Elongated 2-Piece Toilet Dimensions

Back-to-Wall Elongated 2-Piece Toilet Dimensions Diagram

If you have a larger bathroom or taller family members who want something a bit easier on the knees, then consider purchasing something with dimensions like this Back-to-Wall Elongated 2-Piece Toilet. And when it says elongated, it really does mean elongated. From the back of the wall to the forward-most tip of the toilet bowl, this toilet measures 30.5 inches — which is ideal for large bathrooms. But note that this toilet would feel cramped in many smaller half baths. The toilet seat itself spans 18.5 inches long and is just under 14 inches at its widest.

In addition to being long, the Back-to-Wall Elongated 2-Piece Toilet also has some notable height advantages. The seat itself is 16.5 inches above the finished floor. This height allows most average to tall-sized adults to sit very comfortably atop the throne. Furthermore, unlike most compact toilets which have a lower tank behind the toilet bowl, this design allows for a fairly tall secondary unit behind its toilet bowl. Here, the top of the tank reaches an ample 30.75 inches above the finished floor.

Back-to-Wall Round Front 2-Piece Toilet Dimensions

Back-to-Wall Round Front 2-Piece Toilet Dimensions Diagram

For those homeowners who want tall and wide but don’t like the extra-long look of the aforementioned elongated toilet, or who simply don’t have the space in their bathroom for such a model, consider the advantages of the more balanced Back-to-Wall Round Front 2-Piece Toilet.

This toilet is billed as two pieces but they connect snugly together to give the greater impression of one cohesive and nicely balanced unit. From the back of the wall to the forward-most tip of the toilet bowl, the Back-to-Wall Round Front 2-Piece Toilet measures 28.5 inches. This makes it a full two inches shorter than the aforementioned Back-to-Wall Elongated 2-Piece Toilet.

This toilet design features an incoming water supply valve that can be set in two positions. It also has the flush lever conveniently on the upper top left side just below where the 15.75-inch long toilet tank cover rests. This lever faces outward and thereby enables homeowners to put furnishing directly beside the toilet without having issues with people needing to reach to the side to push the flush lever. Note that unlike the first toilet design in our list that boasted the dual-flush mode for better water conservation, this design as it stands only allows for one-size-fits-all flushing capability.

Wall Hung Toilet Dimensions Diagram

Wall Hung Toilet Dimensions Diagram

For those who choose a more modern home design, are installing a toilet in a commercial business or a home repurposed from a commercial business, or who otherwise have a unique design, then you might not have a central sewer pipe, or you may be looking to move it to another location in the building or room.

In any case, the most popular alternative is to hang the toilet on the wall and have the outgoing sewer pipe placed alongside the incoming water pipe. In this case, all the pipework will be in the wall and out of sight.

Wall Hung toilets are attractive as there’s no gunk or build-up that commonly occurs at the base of the toilet because there is no base. Instead, the toilet is hung on the wall and the outgoing sewer pipe cuts through the wall and drains down and out. Where there should be a base, there is empty space, which creates another benefit of making it much easier to clean floors.

Of course, while Wall Hung toilets make things a lot easier in the long-run, they can be frustrating to install. Because most of a person’s weight will rest on the Wall Hung toilet, it is incredibly important that you have it installed on strong through beams and if you aren’t especially handy, that you have someone else do it for you. Installing a Wall-Hung toilet will also usually require some demolition work, as you’ll need full access to the backside of those beams to fully secure the fittings.

Wall-Faced Toilet Dimensions Diagram

Wall Faced Toilet Dimensions Diagram

If you’re nervous about the strength of a Wall Hung toilet, then consider the balance this Wall-Faced design offers. With this Wall-Faced toilet you can enjoy that stable base that will offer ample weight support and you’ll enjoy the side benefit of having the actual water tank portion of the toilet hidden behind the wall.

Like with the Wall Hung toilet design, the Wall Faced toilet will also have the outlet waste pipeline going through the wall. This can help prevent corrosion and leakage issues at the bottom base of the toilet. That said, you will still need to use some floor fixings to secure the toilet in place.

The design here has the toilet sitting about 550 centimeters out from the wall to the outermost tip of the toilet seat bowl. This makes the design a bit more compact compared to other options and a good choice if you’re concerned about space.

Water Closet / Toilet Dimensions Diagram

Water Closet / Toilet Dimensions Diagram

This basic overall toilet dimension drawing helps show the key measurements that you will need to take when researching and choosing a toilet to buy. Note that these dimensions should primarily be used when looking at traditional toilets that have a base that sits upon a finished floor and have an exit waste supply pipe going down through the floor.

For these dimensions, you must look foremost at measurement “A” and measurement “B”. “A” measures the length from the finished floor to the very center of the water exit circumference, or, in other words, the center of where that closet flange will be placed and the bottom of the toilet secured. Measurement “B” will be the height of the toilet bowl.

This measurement is important as it will both determine how comfortable you, your family, and your guests will be when sitting atop the bowl and it will determine how your water supply piping will fit, for example, a higher toilet bowl seat will often require longer water supply piping.

Parts of a Toilet Water Tank (Diagram)

Parts of Toilet Water Tank (Diagram)

This dimension drawing showcases the various parts of your water tank. The most important part to install correctly is the rubber gasket. Also, ensure that the tank-to-bowl gasket fits snugly and there are no tears, cuts, or chips that might otherwise allow water leakage.

Once you have the tank-to-bowl gasket aligned, the next step is to secure the water supply line and screw down the bolts. When installing the other components of the toilet water tank, if they aren’t already installed, the best tip is to start at the bottom and move upward.

Your toilet’s handle fully controls when the water flushes out from the bottom bowl and new water from the tank flows in. When you press down on the lever, it lifts off the flush valve chain, which lifts the flapper, allowing all of the water in the tank to flood into the toilet bowl and thereby push out the excess waste. The other components of the water tank are designed to ensure your tank fills up to the level necessary to complete that whole flushing process again.

Toilet Installation Diagram

How to Install a Toilet Diagram

Picking your preferred toilet dimensions is only the very first step towards enjoying a new throne for your bathroom. The next step is understanding how to install it. We hope this basic installation design helps you learn to place and secure your toilet in the set hole.

Unless you live in a repurposed commercial building or a handbuilt cabin that was designed before basic home zoning recommendations, or you purposely decided to go against the grain when designing your own home, you should have an outgoing water pipe in your floor that will take all waste elimination away from your home and into either your septic system or onwards to your locality’s sewer treatment facility.

This outgoing hole is where you are going to be the central point of your toilet installation process as the holes absolutely must align and everything else can be more readily adjusted, such as adding extra length to your incoming water pipe.

Now that you know where to start, the next step is aligning the closet flange and the bottom of your toilet together so that the wax ring sits snugly within the inner diameter of the closet flange and the closet bolts come through. Note that you will need to apply the recommended manufacturer’s sealant around the entirety of the bottom of the toilet and especially around where the bowl will set on the closet flange. This will prevent any moisture from leaking out.

Once the closet bolts have gone through the necessary holes, place a tapered washer onto the bolt and secure down with an appropriately sized nut. Use a torque wrench to secure the nut and cover that nut with a bolt cap to prevent corrosion issues.

Next, it’s time to add the water tank portion of the toilet bowl. This will be done similarly to how you secured the toilet to the closet flange in that you’ll use the appropriately sized tank bolts, washers, and nuts to ensure that the pieces fit and are tightened down securely with a torque wrench. Pay special attention, however, to the rubber gasket in the included installation diagram to prevent water leakage.

Things To Consider When Buying a New Toilet

When shopping for (or simply researching) a new toilet, it is important to consider the different product features that matter to you. You’ll have to consider important factors outside of your personal taste. For example, you need to know your bathroom layout and pick a toilet that will fit.

There are certain aspects, features, and attributes that you need to consider when shopping for a new toilet

a. Toilet Shape

You might opt for an elongated bowl over a round bowl if toilet bowl shape is something that matters to you. The same goes for toilet seat shape – do you prefer a round toilet seat or an elongated toilet seat? Or, perhaps you simply want a standard toilet without all the bells and whistles.

But what exactly constitutes a standard toilet? It’s important to figure out the dimensions and design to fit your needs.

With modern toilets becoming more and more sophisticated, you can quickly become overwhelmed with new features. Today, there are smart toilets that heat the seat for you, custom-made and even self-cleaning toilets, all of which can be custom made to fit your specific bathroom dimensions – if you know where to look!

b. Toilet Features

You may place importance on the technical features of a toilet – or the aesthetic aspects. For example, if you’re going for a modern bathroom remodel then you may prefer a modern-looking skirted toilet for its aesthetic appeal, rather than a simple wall-mounted toilet that doesn’t look as good.

You should also consider how certain features can improve the functionality of the toilet. For example, a pressure-assisted toilet might be more appealing than a dual flush toilet or a toilet with a bidet seat – if what matters to you most is a clean and powerful flush.


What is the standard size of a toilet?

The general rule of thumb for standard toilet sizing is between 27 and 30 inches deep, the back height is usually between 21 to 31 inches and the width is about 20 inches. It is also important to note that an ada compliant toilet must be of 17 to 19 inches in seat height.

What are the different types of toilets?

There are various different types of toilets. Broadly, we can categorize them as low-level toilets, close-coupled toilets, back to wall toilets, and wall hung toilets.

What’s the difference between a back-to-wall toilet and a wall-hung toilet?

The main difference between a back-to-wall toilet and a wall-hung toilet is that a wall-hung toilet appears to be suspended above the floor, without touching the floor.

How do you measure a toilet?

To measure the width of a toilet, go from the left edge to the right edge of the toilet tank or the toilet seat -whichever is widest. For the depth go from the front of the toilet rim to the back of the toilet and for the height go from the floor to the rim of the toilet seat, then from the seat to the top of the tank.

What is the minimum size for a toilet?

The minimum space required for a toilet is 38 cm from the nearest obstruction. This means the toilet must have at least 38cm clearance from its center line to the nearest object, wall, or any other obstruction.

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