How To Measure Toilet Rough In?

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Last Updated on January 4, 2023 by acechapman

To measure the rough-in size for a toilet, you will need to measure the distance from the wall behind the toilet to the center of the mounting bolts that hold the toilet to the floor.

To do this, you will need to remove the toilet from the floor. Once the toilet is removed, you should be able to see the mounting bolts that hold the toilet to the floor. Measure the distance from the wall behind the toilet to the center of the mounting bolts. This measurement is the rough-in size for your toilet.

This article will explain what rough-in is and how to measure a toilet rough-in. It will also discuss the differences between sizes.

This lesson will clear up all your doubts. Let’s get started with the basics.

What is the rough-in of a toilet?

The rough-in of a toilet refers to the distance from the wall behind the toilet to the center of the mounting bolts that hold the toilet to the floor. This measurement is important when installing a new toilet, as toilets are available in different rough-in sizes and a toilet with the wrong rough-in size will not fit properly.

It is an essential part of every bathroom. It is important to plan in advance for your first bathroom.

While a house is being renovated, it’s hard to make any changes. Keep in mind that it is essential to do the job right the first time. It will only be an additional burden.

The rough-in is the space between the back wall of the toilet and the middle flange of the toilet. The center of the toilet flange corresponds with the location of the bolts that hold the bowl in place.

The standard rough-in for a toilet is 12 inches. However, there are three sizes available on the market: 10-inch, 12-inch, and 14-inch.

10 Inches Rough-In Toilet

A 10-inch rough-in toilet like the KOHLER K-3851-0 Cimarron, which is one of the most popular two-piece toilets, is the ideal choice if you have a small washroom.

This feature, as you know, reduces the space between the wall and the toilet. This feature creates additional space in front of the toilet.

Older homes and offices often have more than 10” of rough-in. Measurements are essential if you want to remodel your bathroom.

12 Inches Rough-In Toilet

All brands now make 12” rough in toilets. It is so popular. This rough-in toilet is a standard feature in modern houses.

A 12” rough in the toilet is more affordable than a 10″ one and takes up less space. This gives your bathroom a sophisticated look.

Toto, American Standard, and Woodbridge all make 12” rough-in toilets for your home.

14 Inches Rough-In Toilet

A 14-foot rough-in toilet is a great choice if you are looking to maximize your toilet. It is difficult to find this rough toilet on the market. This toilet is in very limited supply.

You will likely have to order it if you wish to purchase it. Some manufacturers are producing it.

You now know what toilet rough-in is. But how do you determine it? We will take it one step at a time.

how to measure toilet rough in

How to Measure for a 10-Inch or 12-Inch Rough-In Toilets?

It is easy to measure a rough-in toilet. Tape and space are best.

Three toilets have different measurements:

  • Standard toilets
  • Corner toilets
  • Rare toilets

Standard Toilet Rough-In

Take a measuring tape and measure the distance between the toilet flanges and the back wall in standard toilets. This will give you the answer. This is the best way to find out before installing any toilet.

If the toilet is not installed, the toilet flange will not be visible. Measure the distance between the wall and the center of the bolts. Now you have an idea of how to rough in.

Corner Toilet Rough-In

It can be difficult to measure the rough-in size of a corner toilet. It’s also slightly different.

To record the positions, first, drag the measuring tape from the corners of your commode to where the bolt caps are.

The second step is to draw perpendiculars between the points with a straightedge tool. Each perpendicular will connect to determine the location of the rough-in for the toilet.

Rare Toilet Rough-In

Rare toilets also have an unusual rough-in location.

In this case, the garbage cannot pass through the floor drainage system. The wall integrates the drainage system.

You will need to measure the distance from the polished floor to where the drainage pipe is located.

This information will help you measure the dimensions of your toilet.

When measuring your wall, make sure it is level. The measurement of a decorative wall may vary; an error of one inch could affect your rough-in. Double-check your rough-in before you start.

How to Install a 10-Inch Rough-In Toilet

Let’s say you know the rough-in of your toilet before buying it. If this is the case, you can install any floor-mounted toilet the same way.

The 10” rough in the bathroom is cheaper than other toilets. This saves you money as the plumber fees are too high. Only a few components are required.

Follow the manual’s directions. For your convenience, we also recommend a step-by-step process.

  • First, check that your toilet has a drain pipe at 10”. Install the drainage pipe if it isn’t. Check that your toilet has a wax ring. Place it on the face of the drain pipe.
  • The bolt-holding rings should be placed next to the wax ring.
  • Next, place the bolt so that it faces the toilet you wish to install.
  • Slowly lower the commode to align it with the bolts and wax ring. Make sure the wax ring is secure. Otherwise, leakage could occur.
  • After everything is in place, tighten the nuts. This secures the whole setup.
  • Attach the supply line to your computer and verify all other items. Once you have completed all the setup, make sure to check for leakages.
  • Connect the supply line, and check everything. Once you have completed all the setups, ensure that it doesn’t leak.
  • Your toilet is now ready for use.
how to measure toilet rough in

FAQS on Rough-In Toilets

What is the Difference Between Rough-In 10 Inches and 12 Inches?

There is a major difference between closet flanges in rough 10” and 12”. Because of the space, a 10” rough-in toilet tank will be smaller than a 12” one. A rough toilet 10” is more expensive than a 12” one.

Is it possible to replace a 10-inch toilet with a 12-inch toilet?

Yes. The closet flange must be replaced with an offset flange. This is a complicated job that requires a skilled professional.

I would suggest that you return your 12’’rough toilet and bring a new 10’’ rough toilet. This will then help you save time and money.

What is the Standard Toilet Rough-In Size

The standard rough-in size for a toilet is 12 inches. This means that the distance from the wall behind the toilet to the center of the mounting bolts that hold the toilet to the floor is 12 inches.

Most modern toilets are designed to fit a rough-in of 12 inches, although toilets with a rough-in of 10 inches or 14 inches are also available. It is important to choose a toilet with the correct rough-in size for your bathroom, as a toilet with the wrong rough-in size will not fit properly.


Hopefully, you have learned the factors of how to measure toilet rough-in. The rough-in is a key factor in purchasing a toilet. Choose 10” rough in if your bathroom is small and you need to make adjustments.

Find the top 10-inch rough-in toilets on the market if you’re interested in purchasing a 10” toilet.

You should not only consider rough-in when buying a toilet.

If you are unsure of the rough-in size for your bathroom, you can measure the distance from the wall to the mounting bolts to determine the correct size. You should also consult the manufacturer’s specifications for your toilet to ensure that it is compatible with your rough-in size.

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