How to Measure for Toilet Seat

Your toilet seat has broken, and now you need a replacement, but you’re unsure what to buy. You need something that fits your toilet, which means determining the correct size. Here, we cover how to measure a toilet seat quickly so you can get to shopping as soon as possible.

Tools You’ll Need

• Tape measure (flexible preferred)
• Pencil and paper (or phone) to record measurements
• Optional: Camera or phone if you’re shopping online and want reference photos

How to Measure for Toilet Seat in 3 Steps

1. Bowl Length (Front-to-Center of Bolt Holes)

1. Place one end of your tape measure at the center point between the two bolt holes at the back of the bowl.
2. Extend it straight forward to the outer edge of the front rim.

Bowl length sizes:

• Round bowls: Approximately 16.5 inches
• Elongated bowls: Approximately 18.5 inches

“If your bowl measures closer to 18.5 inches in length, you’ll need an elongated seat,” explains licensed plumber Mike Carter. “Trying to fit a round seat on an elongated bowl will leave too much exposed porcelain.”

2. Bowl Width (Widest Point Across)

This ensures proper width coverage by your new seat.

• Bowl width: Measure across the widest part of your toilet bowl—usually near its midpoint.
• The average width is around 14–15 inches.

3. Bolt Spread (Distance Between Mounting Holes)

This indicates whether standard mounting hardware will be compatible with your new seat.

• Bolt spread: Measure from center-to-center between mounting holes at the back of the bowl.
• The U.S. standard is typically 5½ inches apart.
• If yours differs significantly, check product specs carefully before buying replacement seats.

Understanding Toilet Seat Shapes

Your measurement will help determine which type of seat you need:

Round Toilet Seats

• More compact—ideal for smaller bathrooms or older homes
• Usually ~16.5″ long

Elongated Toilet Seats

• Oval-shaped—offers more sitting space and comfort
• Usually ~18.5″ long

You can browse our collection of one-piece toilets, two-piece toilets, and premium options with built-in features, including integrated bidets, here.

Additional Considerations When Replacing Your Seat

If you’re shopping for more than just basics, keep these factors in mind when choosing your next toilet seat:

• Material: Plastic vs wood vs soft-close options
• Mounting Style: Top mount vs bottom mount bolts
• Add-ons & Features: Bidet seats
• Color Match Tips: If you’re replacing colored fixtures with white ones, double-check the manufacturer’s color codes.

Ensure compatibility by matching all three dimensions—length, width, and bolt spread—with product specifications before purchasing.

– Kohler Installation Guide PDF (Toilet Seats)

FAQ: Measuring for Toilet Seats

Q: What if my measurements don’t match standard sizes?

A: Some older or specialty toilets may have unique dimensions. Contact customer support with photos + measurements—we can help find compatible options!

Q: Can I use an elongated seat on a round bowl?

A: It’s not recommended—it will overhang awkwardly and feel unstable during use. Stick with matching shapes whenever possible.

Q: Do all U.S.-made toilets have standard bolt spacing?

A: Most do (~5½ inches), but always double-check before ordering, just in case yours varies slightly.

Q: How do I remove my current toilet seat?

A: Use a flathead screwdriver under each plastic cap behind the current hinges. Unscrew nuts underneath using pliers if needed.

Resources

For more visual guidance on measuring correctly:

• Video: Choosing the Right Seat
• One-Piece vs. Two-Piece Toilet
• Round Bowl vs. Elongated Toilets
• Measure a Toilet Rough In
• How to Fix a Loose Toilet Seat
• Wood vs. Plastic Toilet Seats

If you’re ready to shop now, explore these helpful categories on PlumbersStock:

• Bathroom Products Overview
• Shop Toilets at PlumbersStock
• Toilets with Built-In Bidets
• Bidet Toilet Seats
• Toilet Seat Replacements
• Toilet Tanks
• Toilet Bowls
• Toilet Supply Lines
• Toilet Fill Valves
• Toilet Flappers
• Wax Rings, Bolts & Caps
• Tank Levers & Handles
• Bathroom Grab Bars

Need help choosing or installing your new toilet seat? Contact our team or browse our full selection of high-quality plumbing products in the bathroom accessories section here.

Save On a Quiet Toilet Seat

We highly recommend opting for a slow-close toilet seat. If you’ve ever been woken up by someone slamming a toilet seat shut, you’ll see the value in this quiet-close feature. If you’ve ever faced the wrath of an angry wife because you were the one waking people up, you’ll see the value in this quiet close feature. They can be expensive, but luckily, we have great deals. You’re going to have a hard time beating these prices:

• Round seat with Slow Close (ProStock TSPR100-SC)
• Elongated seat with Slow Close (ProStock TSPE100-SC) – this is a much cheaper option than the featured Gerber 99-213.

At PlumbersStock, industry professionals can contact us for special deals when they buy in bulk. And homeowners with big projects who buy in bulk can also contact us.