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When you want to replace your toilet, getting the right measurements is crucial. Believe it or not, there are five toilet dimensions you need to know. That way, you can ensure the new one will fit snugly in your bathroom. If you’ve never done this before, start here. We’ll make it easy for you.

There are many other things to consider when you start shopping for a new toilet as well. For example, you’ll likely look at water-saving features and whether it fits with your décor. You may even want it to match your sink. But first, you’ve got to make sure it fits.

Toilet Dimensions: How To Measure the Rough-In

The rough-in of a toilet is the dimension between the center of the flange and the wall behind the water closet. The most common rough-in is 12″. However, you still need to measure it before replacing or installing a toilet just in case. Start by finding the center of the toilet flange. The flange is the pipe fitting that mounts your toilet on the floor and connects it to a drain.

If the toilet is still in place, the center of the flange should align with the rear bolts that keep the toilet attached to the floor. Measure the distance between one of the rear bolts and the back wall to find your toilet’s rough-in. The video below explains how to get the toilet dimensions for the rough-in… And what to do if the current length isn’t long enough.

Two things to keep in mind when measuring the rough-in.

There are two things to keep in mind when measuring the rough-in of a water closet:

  • Tiles and floor molding add thickness to the wall. Most tiles are 3/8” thick, but the thickness of floor molding varies between ½” and 1.”
  • You need to find the measurement between the center of the flange and the stud wall. You will need to add ½” to account for the drywall.

A 12” rough-in is the most common dimension, but you can find rough-ins of 10 or 14” in older homes. Pay attention to the rough-in when checking the toilet dimensions of the unit you want to purchase. You won’t be able to install a water closet with a different rough-in.

You won’t need to measure the toilet’s rough-in if you are installing or replacing a wall-hung model. These toilets don’t have a flange and are connected to a regular plumbing pipe. In order to fit a wall-hung model, you’ll need to measure the height and width of this plumbing pipe.

Water Supply Line Location

If you’re doing a total remodel or building a new home, you can put the water supply line anywhere you want. Otherwise, it’s more economical to work with what you have. Place your tape measure at the center of the flange and run a parallel to the back wall. Mark the spot that is six inches away from the center of the flange along this line. This spot will roughly correspond to the outside of the base of the unit when mounted on the floor.

Draw a line that connects this spot to the back wall. The water supply line should be six or seven inches above the floor along this line. You need to place the water supply line high enough to get clearance from the base trimming. The water supply line is protected by a small flange, so you need to allow enough clearance for the flange as well.

Having seven inches of clearance would be ideal since the flange might touch or slightly overlap with base molding that is 5 ¼” high, especially if you are installing the base molding above the bathroom flooring. It might be best to hire a plumber to install the water supply line for a new toilet. But knowing its location can be useful if you want to start installing base molding in your bathroom.

Here’s a video that explains the water supply line and how to replace it. Older homes may have a brass or lead pipe instead of the more flexible modern ones.

How Much Clearance Do You Need On The Sides Of Your Toilet?

The side clearance of a toilet is something to take into consideration when remodeling a bathroom or shopping for a new toilet. You need enough clearance to use the WC comfortably and to meet building codes. You need to have at least 15” of clearance on each side of your toilet to meet building codes. There are no local variations for this minimum requirement. This means you can’t install your toilet closer than 15” away from a wall, bath fixture, or any other kind of obstacle.

Keep in mind that a 15” clearance is the bare minimum. You can install a toilet further away from the wall or bathroom vanity for comfort. Be careful not to install your WC unit too far away from the wall where you will hang the toilet paper dispenser. It would also be best to limit the side clearance to 15” if you want to install a grab bar on one side of the toilet.

The side clearance of your toilet is something to consider when choosing the bowl shape. If you currently have 15” of clearance on either side of your toilet, measure the width of the bowl at its largest point to get an idea of the toilet dimensions you should look for when shopping.

Toilet bowl designs

You will come across three designs when comparing toilet bowls. These include rounded, elongated, and compact elongated. Elongated bowls are the most common and comfortable design. Round bowls are a common option for smaller bathrooms. Elongated compact bowls are not as popular. However, this design helps you save water and might be more comfortable than a round bowl.

The typical width of a toilet bowl is 14.” The length of a round bowl is somewhere between 16 and 17,” while elongated bowls can have a length of up to 19.” A compact elongated bowl should be somewhere in between the two other designs. Replacing an old toilet is an opportunity to upgrade to a more comfortable bowl design, but check the width and length of the new bowl to make sure you will have enough clearance.

Here’s a video that explains how to take the correct wall measurements.

How Much Front Clearance Do You Need?

You need enough clearance in front of your toilet to easily access it. Limited front clearance can make using the water closet unit very uncomfortable. Local building codes either require 21 or 24” of front clearance. This is the bare minimum. Someone with mobility issues will probably have a hard time getting back up if there is only 21” of front clearance.

If possible, aim to have at least 30” of front clearance for comfort. Don’t hesitate to make some changes to your bathroom layout to have more front clearance for your toilet. You won’t regret it. If there isn’t much space available in front of your toilet, choose a round bowl design. These aren’t as comfortable as elongated bowls but getting enough front clearance should be a priority and even a couple of inches of additional front clearance will make a difference in a small bathroom.

A door that opens and closes in front of the toilet isn’t considered as an obstacle. You need to have at least 21 or 24” of clearance between the front of the toilet bowl and the closed door if it is located directly in front of the toilet.

This video explains how much space to leave in front of your toilet in greater detail.

Choosing The Right Seat Height

The ideal seat height is a matter of personal preferences. If you’re happy with the current one, simply measure from the floor to the seat. Most toilets have a height of 15,” but you can find comfort height models. These models are anywhere between 17 and 19” high, which is similar to a traditional chair.

The standard seat height is 15” because it allows you to adopt a more natural position for eliminating. However, a comfort height seat could be a better experience if you are tall or simply prefer to sit higher. These higher seats also work for those with limited mobility since they make getting back up easier.

If you have children, a 15” seat height is a better choice. Keep in mind that you can also address mobility issues by installing a raised toilet seat. In the end, it is best to try different seat heights when shopping for a toilet. This way, you can determine what feels more comfortable.

Now that you know about the different toilet dimensions, check your local building code to find out how much clearance you need. Take measurements as precisely as possible and don’t forget to check the specifications of the new toilet you would like to purchase to make sure it will fit in your bathroom layout.

How to Measure Your Toilet Dimensions

The video below takes you through each step of measuring your toilet dimensions for a perfect fit.

Featured image for how to measure toilet dimensions: CC0 Public Domain Marina Shemesh via Public Domain Pictures.

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