How to Change a Toilet Seat

Toilet Seat

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Project Overview
  • Total Time: 10 - 15 mins
  • Skill Level: Beginner
  • Estimated Cost: $20 to $50

Toilet seats occasionally need to be removed and replaced when they age out or become damaged. Even if the toilet seat is still in good condition, changing a toilet seat is a fast and inexpensive way to freshen up a bathroom. Few tools are needed and you'll be finished in less than 15 minutes.

Before You Begin

Before buying a new toilet seat, you'll need to know the size and shape of your current toilet bowl or base.

Most toilets in the US are either 16-1/2 inches long or 18-1/2 inches long when measured from front to back. Toilets that are 16-1/2 inches are called rounded toilets because they have a generally round shape. Toilets that are 18-1/2 inches are called elongated toilets and have an oval shape. A less common toilet, also 18-1/2 inches long, is called a compact elongated toilet and has a shape somewhere between round and oval.

Purchase the correct size and shape of toilet seat for your toilet since they cannot be cross-matched. Toilet seats and lids are usually sold in combination. There are some toilets, especially one-piece toilets, where the design is custom to the point where only an exact replacement seat will fit. It is neither a round-front or elongated toilet seat.

Safety Considerations

Areas of the toilet around and below the toilet seat, rim, hinges, and bolts may contain contaminated waste material. Before changing the seat, thoroughly clean the toilet with a disinfecting solution. Further protect your health by wearing latex or nitrile gloves, eye protection, and breathing protection.

In some cases, where the toilet seat has metal bolts, they will rust and freeze and become impossible to unscrew. In this case, extra care must be taken and the bolts must be cut off by hand.

What You'll Need

Equipment / Tools

  • Screwdriver
  • Measuring tape
  • Pliers or wrench set
  • Latex or nitrile gloves


  • Toilet seat


  1. Remove Old Toilet Seat Hinge Caps

    Your existing toilet seat and lid has two hinges toward the back of the seat. Caps conceal the hinges. Since there are many cap configurations, they may individually flip up (toward the back) or in combination, with platform-style hinges. Or the hinge caps may twist counter-clockwise (with easy-clean models). Some older-style caps are not hinged. These loose caps each come up individually.

  2. Remove Bolts From Old Toilet Seat

    Most toilet seats have plastic bolts that extend down through the toilet rim. Plastic nuts under the rim can be loosened by hand. If the bolt appears to be rotating while you are turning the nut, hold the top of the bolt in place with a flat-head screwdriver. In some cases, you can simply press the top of the bolt with your thumb to prevent it from rotating.


    If the plastic nuts are difficult to remove from the bolts, squirt some penetrating solution like WD-40 on the bolts. After a few minutes, try loosening the nuts again.

  3. Remove the Old Toilet Seat

    After removing the plastic nuts, lift the toilet seat up. The bolts should come up with the seat.

  4. Measure Toilet

    Use a tape measure to measure the toilet bowl at the rim. Purchase a new toilet seat based on these measurements.

    Confirm that the distance between the two bolt holes is 5-1/2 inches. Measure from the center of one hole to the center of the other hole.

    Run the tape measure along the length of the toilet. Start at the center of the bolt holes and end at the outer rim of the toilet. The distance should be either 16-1/2 inches or 18-1/2 inches. Either measurement may vary slightly (1/8-inch or so).

  5. Insert Plastic Bolts

    Conventional hinge: Open each hinge. Insert the plastic bolts through the square washers and then through each hinge. Close the hinge caps. Slide each hinge into the back end of the toilet seat.

    Platform hinge: Insert the plastic bolts through the square washers and then through the single connector bar. Rest the bar in place on the toilet, pushing the bolts through the holes on the toilet rim.


    Use only the manufacturer-supplied plastic bolts and nuts. Though some types of metal hardware may work if properly tightened, metal hardware potentially may crack the porcelain toilet rim. Plastic hardware will not break the porcelain.

  6. Add Toilet Seat

    Conventional hinge: Fit the bolts through the holes on the toilet rim. Hold the top of the bolts in place with the screwdriver while turning the plastic nuts into place from below the toilet rim.

    Platform hinge: Fit the plastic bolts through the holes on the toilet rim. From below, add the plastic nuts. Flip up the single, connected hinge cap. Slide the toilet seat into the platform hinge, then close the hinge cap.


    Some bolts have a snap-off feature. The end of the bolt is designed to snap off in the pliers or wrench once the main body of the bolt has achieved proper tension.

When to Call a Professional

Rarely is it necessary to call a plumber to change a conventional toilet seat. But you may want to have a plumber assist you with changing a unique toilet seat such as an electronic bidet seat or an electric heated toilet seat.