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How to Install a Toilet

Holly Honeycutt

By Holly Honeycutt
Updated November 13, 2023

Do you have a toilet that’s not working or doesn’t fit the bathroom décor? Once you choose your new toilet, replacing and installing a new toilet gives you a fixture that looks better and can help save on water bills. Learning how to install a toilet isn’t difficult. We’ll show you how to do it.

Skill

Intermediate

Time

Few Hours

Tools and Materials

Note

Product costs, availability and item numbers may vary online or by market.

Measuring For a New Toilet

A person using a tape measure to measure for a new toilet.

Learning how to replace a toilet starts with knowing how to size the fixture. The right dimensions for a toilet depend on the size of your bathroom and the location of the floor drain. You’ll see toilets listed by rough-in size. To determine the rough-in size you need, measure from your back wall to the center of one of the closet bolts that secure the existing toilet to the floor. Be sure to measure from the wall and not from the baseboard. A rough-in size of 12 inches is the most common, but you may see 8-inch or 14-inch rough-in measurements as well.

Next, measure to any nearby water supply lines on the floor. Some toilets have a wider base that might not fit next to a supply line. It’s also a good idea to measure from the bowl to a sidewall to be sure that the toilet will fit in your space.

If you have shelves or a cabinet above your toilet, you’ll also need to consider the tank height. To determine your existing toilet tank height, measure from the floor to the top of the tank lid.

Choose the shape of your toilet bowl. Usually, toilet bowls are elongated for comfort, but if you have a smaller space you might need a round bowl. The shape will determine the toilet seat size. While toilet seats are generally standard sizes, it’s a good idea to have measurements when shopping in case there are some variations by manufacturer. Here’s how to measure toilet seat fit by collecting measurements from the toilet bowl.

  1. Remove the seat and measure from the center space between the seat bolt holes to the front edge of the bowl. Round bowls should measure 16-1/2 inches, while elongated bowls should be about 18-1/2 inches.
  2. Measure the distance between the center points of the bolt holes. This distance should be 5-1/2 inches.
  3. Measure the distance between the outer edges of the bowl at the widest point. This will usually measure between 14 and 14-1/2 inches.

Removing the Old Toilet

Once you have the new toilet, start removing the old one. Key steps include turning off the water, draining the tank, popping off the toilet bolt caps to unbolt the toilet and lifting the toilet up and away from the toilet seal or wax ring.

Steps for Removing a Toilet

Installing a New Toilet

How do you install a toilet? The key steps are relatively simple and include placing new hardware and a new wax ring, securing the new bowl to the floor, attaching the tank and installing the seat. Here are the details for a typical project.

Steps for a Toilet Install

Good to Know

If you don’t have the time or skill needed to complete this project yourself, Lowe's has you covered with our toilet installation service.

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