How To Install A New Toilet Seat

Achieve a perfect fit using our guide to install your brand-new toilet seat, featuring step-by-step photos for each installation stage.
Written By: Richard Morgan | Updated:
How To Fit A Toilet Seat
Richard Morgan/DIY Works

Fitting a new toilet seat isn’t the most luxurious DIY task to complete, but it’s relatively straightforward, and it can make a big difference.

Whether you want to fit a soft close, wooden or basic seat to your toilet, the process is the same. There are only minor differences with regard to the fitting, which includes top or bottom fixings and screws or nuts for tightening.

If you are wondering how to fit your new toilet seat, below is our tutorial for the replacement.

How To Measure A Toilet Seat

To avoid any issues arising when you come to fit your new toilet seat, you’ll want to ensure that it actually fits your toilet correctly beforehand.

To do this, you have two options to consider, which are to either buy the same toilet seat as the old one that was fitted or to measure the toilet to choose a different seat.

In terms of measuring the toilet seat, you’ll want to measure the following:

  • Length between the fixing holes and the end of the toilet
  • Width across the pan (at its widest point)
  • Height between the fixing holes and cistern or wall
  • Distance between the two fixing holes (most seats are universal, so the distance isn’t much of an issue)
How To Measure A Toilet Seat

Richard Morgan/DIY Works

With the measurements available, you can browse the latest range of toilet seats to find your perfect seat. As you can imagine, there is a huge selection available that includes a soft close and quick release mechanism and many luxury designs.

What You’ll Need

  • Cleaning spray and cloth
  • New toilet seat
  • Fixings that are supplied with the seat
  • Screwdriver or spanner (depending on fixings)

How To Fit A Toilet Seat

1. Remove The Old Toilet Seat

To begin fitting a toilet seat, you’ll first need to remove the old one that’s connected to the toilet. Depending upon whether it’s a top or bottom fixing will determine how you remove it. If it’s a top fixing, you’ll need to remove any covers upon the seat that are hiding the fixings and then proceed to loosen the screw or nut. However, if it’s a bottom fixing, you’ll need to look underneath the toilet to reveal the bolt holding it on.
how to remove toilet seat

Richard Morgan/DIY Works

After loosening the screw or nut, you should find that the seat can now be pulled away from the toilet. As you can see in the photo, this particular seat had rusted away from the metal fixings, so it needed to be replaced.

2. Clean Up The Area

Although optional, it’s a good time to clean up the toilet seat where the original fixings for the old seat were fitted. After the removal, you may find there are areas that you were unable to clean with the seat fitted.

3. Assemble The Fixings

The next step is to check the fixings that were supplied with your new toilet seat and assemble them if required. Once assembled, you can put them in place to test fit and see if they are compatible with your toilet (as shown below).

how to replace toilet seat

Richard Morgan/DIY Works
how to change a toilet seat

Richard Morgan/DIY Works

4. Thread The Fixing Into The Toilet & Tighten

Once you are happy that the fixings are compatible, you can continue to install them properly. This will involve putting them in position and tightening the screw or bolt so that the toilet seat can be installed without any movement.

Although you may be tempted to leave out the washers, they play an important role in tightening the toilet seat. Therefore, ensure they are fitted in the correct order because many seats come with multiple washers.

how to change toilet seat

Richard Morgan/DIY Works

With regards to tightening the toilet seat, we would recommend that you only tighten the screw or nut to about 80% at this stage. This is because you may need to align the toilet seat, as shown in the next step.

5. Fit & Align The Toilet Seat

With all of the hard work of installing the fixings complete, you can now fit the toilet seat and begin to align it correctly. Depending upon the type of toilet seat you have, you may have a quick-release mechanism (as shown in the image) or need to screw the seat onto the fixings.

To align the toilet seat, put the lids down and align it with your hands on each side. Ideally, you want the shape of the toilet to match the seat (this should be the case if it’s a compatible toilet seat). Once you are happy with the alignment, you can proceed to tighten the toilet seat (try to avoid overtightening it).

how to put toilet seat on

Richard Morgan/DIY Works

6. Test The Seat

After you have fully tightened the toilet seat, you can proceed to test it to ensure everything is working as it should. For example, we would recommend that you test the following:

  • Soft close works on each lid
  • Quick release mechanism releases with ease
  • All lids can lift without falling downwards
  • The seat doesn’t move when you sit on it
how to fit toilet seat

Richard Morgan/DIY Works

If your toilet seat passes each of the above tests, congratulations, you’ve installed the toilet seat correctly.

How To Tighten A Toilet Seat

After fitting your new toilet seat, if you find that it has started sliding sideways or moving in general, it’ll need further tightening. In terms of how to tighten a toilet seat, it’s relatively straightforward regardless of whether it’s fixed at the top or at the bottom (as shown in the photo). To tighten a toilet seat, you’ll need a screwdriver, spanner or the supplied tool that came with the seat to tighten the screw or nut.

If the toilet seat is fixed at the bottom, simply proceed to tighten the nut or screw clockwise under the toilet to tighten the toilet seat (as shown in the photo).

how to tighten a toilet seat

Richard Morgan/DIY Works

However, if the toilet seat is fixed at the top, you’ll likely need to remove the toilet seat from its fixing and remove a cover to access the nut or screw for tightening.

As you tighten the toilet seat, you’ll want to ensure the toilet seat remains aligned correctly on the toilet. You’ll also want to avoid overtightening the seat because it could lead to the bolt breaking or stripping.

If you find that the toilet seat is still moving or sliding sideways after tightening it, you may need to insert a washer on the nut between the bolt and the underside of the toilet. This has proven to be very successful for us with certain toilet seats.


Removing and fitting toilet seats is a task that we do regularly due to the multiple properties we maintain. However, the process is very similar regardless of the toilet seat that you need to fit, and it’s very straightforward.

Hopefully, our guide has walked you through the entire process and given you the confidence to try it out yourself. However, if you need further assistance, feel free to get in touch, and we will try to help wherever possible.

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