white ceramic toilet bowl

How to Measure a Toilet

When it comes to replacing or installing a new toilet, accurate measurements are crucial. Knowing how to measure a toilet properly will ensure that you choose the right size and fit for your bathroom. In this guide, we will walk you through the step-by-step process of measuring a toilet.

Tools You Will Need

Before you begin, gather the following tools:

  • Tape measure
  • Pencil and paper

Step 1: Measure the Rough-In

The first and most important measurement you need to take is the rough-in. The rough-in refers to the distance between the wall behind the toilet and the center of the toilet flange, which is the pipe that connects the toilet to the sewer.

To measure the rough-in, follow these steps:

  1. Locate the center of the toilet flange. This is usually a round opening on the floor.
  2. Place the end of your tape measure against the wall behind the toilet.
  3. Extend the tape measure to the center of the flange and read the measurement. The most common rough-in size is 12 inches, but it can also be 10 or 14 inches.
  4. Write down the rough-in measurement.

Step 2: Measure the Bowl Shape and Size

Next, you’ll need to measure the bowl shape and size. There are two common bowl shapes: round and elongated. Round bowls are typically shorter and take up less space, while elongated bowls provide more comfort.

To measure the bowl shape and size, do the following:

  1. Measure the distance from the center of the flange to the front edge of the toilet bowl. This will give you the bowl length.
  2. Write down the bowl length measurement.
  3. Determine the bowl shape by measuring the width of the bowl at its widest point. Round bowls are usually about 16.5 inches wide, while elongated bowls are around 18.5 inches wide.
  4. Write down the bowl shape (round or elongated) and width measurement.

Step 3: Measure the Tank

The next measurement you’ll need is for the tank. The tank is the upper part of the toilet that holds the water for flushing.

To measure the tank, follow these steps:

  1. Measure the width of the tank from side to side.
  2. Write down the tank width measurement.
  3. Measure the depth of the tank from front to back.
  4. Write down the tank depth measurement.

Step 4: Measure the Height

Lastly, you’ll want to measure the height of the toilet. Standard toilets are usually around 14 to 15 inches high, while comfort or ADA-compliant toilets are taller at around 17 to 19 inches.

To measure the height, do the following:

  1. Measure the distance from the floor to the top of the toilet seat.
  2. Write down the height measurement.


By following these steps, you can accurately measure a toilet for replacement or installation. Remember to record all the measurements carefully, as they will be crucial when shopping for a new toilet. Having the right measurements will ensure a proper fit and functionality in your bathroom.

Now that you know how to measure a toilet, you can confidently choose the right size and style for your bathroom renovation or upgrade.

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