Measuring Toilet Rough in Dimensions – A Detailed Guide

Written by

Paulk Webb


Freddie J. Hagopian

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measuring toilet rough in dimensions

Measuring toilet rough in dimensions is a challenge that all homeowners will encounter eventually. It calls for keen attention to details, perseverance, and patience. After all, getting accurate measurements can save you money and space for your bathroom.

Fret not, because this article will teach you detailed methods on how to do the task like a veteran. When measuring the rough-in, you’ll need to determine the distance between the toilet flange’s center and the wall.

Measuring Toilet Rough-in


To measure a toilet for replacement or for any other reasons that require the rough-in, height, and length of a toilet, you will need to secure yourself the following tools to effectively carry out the task:

  • Tape measure
  • Pen and paper to write down your measurements; find a space for writing inside the bathroom.
  • Framing square

Starting with the basics, the rough-in size of a toilet is determined by measuring the space from the center of a toilet flange from wall. A toilet rough in measurement is a very crucial thing to consider, especially if you are looking for a new toilet.

#1 Measuring a Toilet Rough-in With the Absence of an Existing Toilet

Due to the fact that there is no need to take into account an existing toilet, which could make the measuring procedure more complex, this is the easiest method to follow when measuring a toilet rough-in.

  • Determine the specific placement of the drainpipe. In doing so, keep in mind that it looks like a circular opening with bolts.
  • With your measuring tape, find the distance between the center of the drainpipe and the wall, then record the measurement. Make sure the tape reaches the naked wall instead of the moldings.
  • The standard measure rough in for toilet is 10 or 12 inches. That’s why it is easy to find toilets for a 10 inch or 12 inch rough-in. If you have an old home, you may get a 14-inch

#2 Measuring Standard Toilet Rough-In

Having an existing toilet in your bathroom is not a hindrance to determining a toilet rough-in size. Consider the following steps to acquire the rough-in measurements without removing toilet.

  • Rather than looking for the drainpipe, locate the screws that connect your toilet to the bathroom floor instead. This will serve as the first reference point for your measurement.
  • Determine toilet rough in size by measuring the distance between the center of the aforementioned screws from the naked wall.
  • Do the above steps multiple times for the accuracy, especially if you get an irregular number (not 10, 12, or 14).

For instance, a result of 12.5 inch toilet rough-in already exceeds the standard size of 10 or 12 inches and is insufficient for a rough-in of 14 inches. Such a situation calls for a second investigation.

#3 Measuring a Corner Toilet Rough-in

From simple steps to be taken to measure rough in size for the toilet, let us move on to more complex procedures in measuring a corner toilet rough-in.

  • Find the location of the screws securing your toilet to the bathroom floor. By doing this, you can then roughly determine where the drainpipe or toilet flange is placed because they are frequently found halfway between the screws.
  • Make the center of the drainpipe as your first point and the wall as the second point.
  • To properly take the corner toilet rough-in, take the measurements at a 90 degrees angle from the drainpipe towards the left and right sides of the wall.
  • Mark the points where your tape reaches on both wall sides, and draw two perpendicular lines from them. Where the lines meet is the rough-in point.

#4 Measuring Rough-in of Wall-Mount or Rear-Outlet Toilet

Get the vertical distance between the floor and the center of the waste drain to obtain the rough-in measurement.

Measuring Other Toilet Dimensions


1. Toilet Height

  • To measure the toilet seat, you simply need to measure from the bottom of the floor to the seat.
  • If you have a shelf or cabinet above where your toilet will be installed, you should determine the height of the toilet tank as well. Make sure there is enough vertical clearance between the tank and the shelf.

Read more: Standard height vs comfort height toilet: which is better?

2. Toilet depth

  • The depth is the distance from the toilet’s back to the rim. Usually, this measurement should be 27 to 30 inches.

3. Toilet width

  • To gauge the width of a toilet, measure either the widest section of the bowl or the broadest part of the tank. It is advisable to take the wider part.
  • No matter where it is located in your bathroom, the toilet needs at least 30″ of space to be comfortable.

Frequently Asked Questions


What is a toilet rough-in?

Essentially, the distance from the wall to the middle of a toilet drainage pipe, sometimes referred to as the toilet flange, is the rough-in size of a toilet.

Why is the rough-in dimension essential?

Measuring rough in for the toilet is an essential procedure since the rough-in determines whether a new toilet can be installed. Additionally, you can create more space in your toilet room if you can reduce the rough-in.

What are the standard toilet rough-in dimensions?

Here are the toilet rough-in dimensions, from most to least common: 12 inch, 10 inch, 14 inch.

You have an unusual toilet if your rough-in dimension has a 12.5 inch toilet rough-in or is not one of the mentioned lengths.

How do I know if I need a 10 inch or 12-inch rough-in toilet?

The telltale sign you need a 10 inch or 12 inch rough-in toilet is the space of your bathroom. If your bathroom is spacious enough, you should opt for a 12-inch since it’s the standard dimension for rough-ins. Otherwise, you should go for the 10-inch type.

What are the standard toilet installation measurements?

A normal toilet will have a depth of around 30 inches, a rear height of approximately 30 inches, and a width and seat height of roughly 20 inches.


Measuring toilet rough in dimensions is a time-consuming job. However, if you want to replace this sanitary unit, knowing how to properly determine toilet dimensions inches is necessary.

Standard rough-in only comes in three sizes: 10, 12, and 14 inches, but some homeowners’ bathrooms call for 11 inch rough-in.

You can refer to a diagram online if you want to know the exact model of your toilet and its actual rough-ins without measuring. This can save you a lot of time and work.

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