Informational Guide

How To Measure A New Toilet Seat Correctly (2023 Guide)

Get the throne right! Learn how to measure a toilet seat correctly with our complete sizing guide.

by Andrew

People often underestimate the benefit of a good toilet seat. An ill-fitting toilet seat will be uncomfortable to sit on, can break under stress, and can be challenging to install.

So if you are remodeling your toilet, you should make sure you get a toilet seat that fits properly.

  • Length
    The length refers to the distance from the mount on the back to the tip of the front of the seat. If the seat is too long or too short, it won’t line up with the rim of the toilet bowl. This can cause fractures and bending from sitting because weight won’t be evenly distributed.
  • Width
    Similarly with width. If the seat is too wide or not wide enough, it will not sit on the rim of the bowl. You want the feet on the bottom of the rim to line up with the rim of the bowl.
  • Drill hole spacing
    If the drill hole spacing is off, then you won’t be able to connect the seat to the hinge. Improperly spaced drill holes are at risk of cracking or breaking under pressure.

toilet set

Things to Keep in Mind When Measuring a Toilet Seat

Measure at the Widest or Longest Part

When measuring the width, make sure that you measure between the two widest points on the sides of the seat. For length, you want to measure from between the drill holes on the back of the seat to the edge of the front.

Double Check Seat Dimensions

It’s a good idea to pick a few sets of points to measure and choose the longest ones, so you are sure you are making the right measurements. It is ok if your measurements are off by a slight bit, like a centimeter or so. Most toilets have a bit of wiggle room on seat size.

Popular Standard Seat Measurements

Toilet seats are all a bit different, but there are some standard measurements out there. Common measurements for toilet seats include:

  • Width 35 cm, length 40-41 cm
  • Width 36 cm, length 40-41 cm
  • Width 37 cm, length 41-48 cm
  • Width 38 cm, length 41-48 cm

You also need to make sure that the shape is right. Some bowls are more elongated, while others are more round.

Standard Measurement for Distance Between the Fixing Hinges

Most toilet seats attach using two bolts on the back. It is crucial to get this measurement right, or else you won’t be able to bolt on the hinge. Standard distances between drill holes are:

  • 7-16 cm
  • 9-20 cm
  • 10-18 cm
  • 11-21 cm
  • 14-19 cm
  • 15-16 cm

8 Easy DIY Steps to Measure a Toilet Seat

  • 1
    Determine if the toilet seat needs fixing.
    You can tell if your seat needs replacing if the paint is thinning/chipping, there are cracks on the bottom or near the bolt hinge, or your seat exudes a foul odor. A foul odor can mean your seat has holes in it.
  • 2
    Remove the old toilet seat
    It probably seems obvious, but it helps to first remove the old seat before measuring. You can take the seat off by removing the two bolts on the back. These bolts can typically be pulled out by hand (with gloves!).
  • 3
    Determine the shape of your toilet
    Most toilet bowls have an “elongated” gourd-like shape. Others have a more round, circular appearance. It helps to take reference pictures so you can find a seat with the right shape.
  • 4
    Measure the length of the seat
    Starting from right between the drill holes, measure to the edge of the front end of the bowl. Make sure you are measuring at the longest point of the toilet.
  • 5
    Measure the width of the seat
    Starting at the two widest points of the bowl, measure the width. It can be hard to tell exactly where it is the widest, so it helps to pick a few pairs of points, measure them, and pick the longest distance.
  • 6
    Measure the distance between fixing holes
    Next, measure the distance between the two drill holes. You want to measure from the center of each hold, not the inner or outer edges.
  • 7
    Measure the wall gap
    If you have a tankless toilet, measure the space between the drill holes and the wall behind it. You want at least an inch of space so the toilet seat can rest upright against the wall.
  • 8
    Decide on a new toilet seat & replace
    Now that you have all the necessary measurements, it’s time to pick a new toilet seat and attach it. The new seat should be easy to install with the premade drill holes.

People also Ask (FAQs)

Do brands have different sizes for toilet seats?

Yes, brands have different sizes for the same model toilet seat. That way, you have some flexibility in what you choose.

Which is better, a round or elongated toilet?

It’s purely up to preference. Some people prefer round toilets because they give more support when sitting, and others like elongated toilets because they are larger.

How do I know what size seat I need?

The only three measurements you need to know are the length, width, and space between the drill holes.

How do I measure a toilet seat?

It’s very easy. Just make sure that you measure the longest and widest parts of the seat and follow our guide above.


A good toilet seat is a necessary fixture of any bathroom. Replacing an old toilet seat is a cinch too. Just make sure you keep the measurements consistent and use your judgment to find the right new seat.