Toilet Seat Hardware

Toilet seat hardware fits the first time when you take three measurements before you leave the house: the bowl shape, the bolt spread and the mounting type. Get those right, and the rest is a short job.

Here’s the whole game. A round bowl is roughly 16.5 inches from the center of the mounting holes to the front, while an elongated bowl is approximately 18.5 inches. Then check your bolt spread: the standard spacing is 5.5 inches center-to-center on nearly all North American toilets. Last, look under the rim: if you can reach nuts under there, it’s bottom-mounted, the common kind. If you can’t reach underneath, as on many one-piece and skirted toilets, the seat needs top-mount hardware that tightens from above; buy a seat made for top mounting and use the hardware it comes with.

Measure, confirm the mounting, then pick your seat.

Picking the Seat

Bowl shape decides the seat, and round and elongated don’t swap. WBC’s seats, all white:

Seat	Shape	What it’s for
Closed-front seat	Round	The everyday replacement
Closed-front seat	Elongated	The everyday replacement for elongated bowls
Wood closed-front seat	Round	Heavier, solid feel, warmer to sit on
Wood closed-front seat	Elongated	Same, for elongated bowls
Sculpted closed-front seat	Round	A contoured look
Seat with chrome hinge	Round	Metal hinges for a sturdier, dressier hinge
Child/adult seat	Round	A built-in child seat that folds down over the adult ring, for potty training
Open-front commercial seat	Elongated	Shops, offices and public restrooms

Wood seats are heavier and feel more solid; plastic seats are lighter and shrug off cleaners. The child/adult seat saves you buying a separate trainer seat and wrestling it on and off.

Hinge Bolts: Replace Them, Don’t Fight Them

A wobbly seat is usually the bolts, not the seat. WBC carries a nylon toilet seat bolt kit and toilet seat hinge bolt sets in two styles.

Plastic and nylon bolts are the right material for this job. They can’t rust, so they don’t seize the way plain steel does in that damp spot, where a rusted bolt can mean cutting it off with a hacksaw a few years later.

Bring the old bolt along if you can, and match its length and how it attaches to the hinge.

Installation Without Cracking the Bowl

The way this job goes wrong most often is overtightening into porcelain.

• Line up the seat, then snug the nuts alternately, left then right, so it sits square instead of cocking to one side.
• Snug, not cranked. Follow the seat’s tightening instructions. Plastic bolts snap or strip if you muscle them, and porcelain cracks before a metal bolt gives.
• If it still wobbles, don’t crank harder. Check that the bolts are the right ones for that seat’s hinges, replace worn ones, and use the washers that came with the seat.

Pulling old corroded hardware is its own fight. Hit seized nuts with penetrating oil and give it time. If a metal bolt is rusted solid, cut it with a hacksaw rather than forcing it: forcing a corroded bolt is exactly how a bowl ends up cracked.

Frequently Asked Questions

How do I know if I need a round or elongated seat? Measure from the center line of the mounting bolt holes to the front edge of the bowl. Around 16.5 inches means round; about 18.5 inches means elongated. The shapes aren’t interchangeable.

What’s the standard bolt spacing for a toilet seat? 5.5 inches center-to-center between the two mounting holes, standard on nearly all North American toilets. Still measure yours before buying.

Should I use plastic or metal hinge bolts? Plastic or nylon for a standard seat. They can’t rust, so they’re much easier to get off years later than plain steel in a damp bathroom.

My seat wobbles even after tightening. What’s wrong? Don’t keep cranking: that’s how porcelain cracks. Check the bolts and washers against the seat’s instructions, and if the bolts are worn or stripped, replace them with a new bolt kit.

The old bolts are rusted solid. How do I get them off? Soak the seized nuts in penetrating oil and let it work. If they still won’t budge, cut the bolts with a hacksaw. Never force a corroded metal bolt; a new bowl is a far bigger job than a new seat.

What’s a child/adult toilet seat? A seat with a smaller child ring built in that folds down over the regular seat, so a toddler can use the toilet without a separate trainer seat. Lift it out of the way for adults.