Whether you're replacing a broken toilet seat, upgrading for comfort, or simply giving your bathroom a fresh look, choosing the correct size is essential. Toilet seats come in a few standard shapes and sizes, so measuring accurately will ensure a perfect fit.
This guide will walk you through everything you need to know about how to measure a toilet seat, step-by-step.
Why Measuring Your Toilet Seat Matters
Toilet seats are not one-size-fits-all. A poorly fitting seat can be uncomfortable and even unsafe. Most toilet bowls are either round, elongated, or in some cases, D-shaped (common in European toilets). Knowing the shape and size ensures:
Comfort
Proper alignment
Stability
Aesthetic consistency
Tools You'll Need
Before you begin measuring, grab the following tools:
A tape measure (preferably a flexible one)
A notepad and pen to jot down measurements
A camera or phone (optional, for reference)
Step-by-Step Guide to Measuring a Toilet Seat
Step 1: Identify the Shape of the Bowl
Look at your toilet bowl from above. Toilet bowls typically fall into one of these categories:
Round – More circular in appearance, common in older homes.
Elongated – Oval-shaped and longer, more common in modern bathrooms.
D-Shaped – A flat-backed, modern oval shape.
Once you identify the shape, it’ll help guide your measurements and your choice.
Step 2: Measure the Length
Measure from the center of the two bolt holes (at the back of the seat) to the front edge of the bowl.
Round toilets: Typically about 16.5 inches (42 cm)
Elongated toilets: Usually around 18.5 inches (47 cm)
Record this measurement – it's the most important one.
Step 3: Measure the Width
Measure the widest part of the bowl from one outside edge to the other (side to side). This is usually fairly standard, around 14–14.5 inches (36–37 cm), but it’s still essential to check.
Step 4: Measure the Bolt Spread
Measure the distance between the two bolt holes at the back of the toilet bowl.
In the U.S., the standard is 5.5 inches (14 cm)
In other regions, it may vary – check carefully
This measurement ensures your new seat will attach securely.
Step 5: Optional – Measure the Seat Itself
If you're replacing a seat and don’t want to measure the bowl, you can measure the old seat:
Length: Back hinge to front edge
Width: Widest point across
Bolt spread: Distance between hinge holes
Just make sure the old seat was a good fit!
Tips for Buying a New Toilet Seat
Match the shape exactly – round vs elongated.
Choose material: plastic, wood, soft-close, heated, etc.
Check weight capacity if needed.
Consider features: nightlight, bidet function, quick-release hinges.
Common Mistakes to Avoid
Measuring the lid instead of the bowl.
Assuming the toilet is a standard size without checking.
Forgetting to measure bolt spread.
Buying for the wrong shape (round vs elongated).
Conclusion
Measuring a toilet seat is quick and easy, but it makes all the difference when choosing the right one. With the right measurements in hand – length, width, and bolt spread – you’ll be able to find a seat that fits perfectly, functions well, and enhances your bathroom’s comfort and appearance.