Project Guide

How to Install a Toilet Seat

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How to Measure a Toilet Seat
A person measures a toilet seat lengthwise with a tape measure.

Before buying a new one, use a tape measure to determine what size toilet seat will fit the bowl.

  • First, find the bolts where the seat attaches to the bowl and measure the distance between them. The standard measurement is 5 1/2 inches. 
  • Measure the width of the bowl at its widest point. 
  • Measure the length of the bowl from between the seat bolts to the outer edge of the front of the bowl. Round bowls should have a length of about 16 1/2 inches and elongated bowls should be 18 to 18 1/2 inches. 
Choose the New Toilet Seat
A selection of six toilet seats of different colors.

Choose among the different types of toilet seats for your replacement. 

  • Most toilets are made of high-impact plastic or a plastic coating over wood, while enamel, natural wood, molded wood, bamboo and fiberboard are other options. 
  • Toilet seat shapes are generally either standard (round) or elongated. 
  • “Whisper close” lids have a popular design to prevent the seat from loudly slamming shut. 
  • A specialty item such as a raised or heated toilet seat may have special installation requirements: check manufacturer's instructions.

Tip: Toilet seats come in many colors. Consider the stylistic statement of a contrasting color, such as a black seat on a white toilet. 

Remove the Old Toilet Seat
A person lifts out an old toilet seat and cleans around the bolt holes.
  • Before removal, clean the old seat as well as the toilet bowl and rim. 
  • At the back of the bowl, locate the seat bolts that secure the seat to the bowl. Pop off the bolt covers, if required. A screwdriver may be necessary. 
  • Look at the back of the bowl for the nuts that attach to the bolts. Loosen the nuts from the bolts by hand or with an adjustable wrench, turning counterclockwise. Remove the nuts from the bolts and washers, if they’re also attached. 
  • Remove the bolts and lift the old seat and its hinges from the toilet. Recycle the old seat and any parts, if possible. 

Tip: If the old toilet seat bolts are stubborn, you may need to loosen them with a spray of penetrating oil or cut them off with a small hacksaw. 

Position the New Toilet Seat
A person positions a new toilet seat over a toilet before installation.
  • Remove the new seat from the packaging. The new seat should include all mounting hardware you need. 
  • Place the new toilet seat lid atop the rim, with the new seat hinges aligned over the holes for the bolts. 

Tip: Use a level if you want to confirm that the seat is even. 

Attach the New Toilet Seat
A person aligns the toilet seat bolts bolts over the holes while installing a new seat.
  • Feed the bolts through the holes in each hinge and the toilet bowl, with the head of the bolt on top. 
  • Attach the nuts to the other end of the bolts and tighten clockwise by hand and then with the wrench to insure a firm connection. If your hardware includes a pair of washers, put them on the bolts before the nuts. 
  • If the hinges have plastic covers, snap them in place. 
  • Open and close the lid and jiggle the seat to confirm that it’s secure. 

Knowing how to install a toilet seat is one of the easiest plumbing-related tasks and can give your bathroom a quick face lift.