Toilet Seats 101

Toilet seats are to toilets like tires are to cars. 

Goodyear, Firestone, Michelin, etc. each fit Ford, Chevrolet, Toyota, etc.  Chruch, Olsonite and Bemis all fit Kohler, American Standard, Eljer normal-style toilets.  Typically the brand of the seat is not the brand of the toilet.  Exceptions are some seats from Kohler and American Standard toilets which are branded Kohler or American Standard.  These were probably sold with the original toilet and were private-labeled for them by OEMs such as Bemis, but still any seat brand will fit all toilet brands. Hence for example, if you are replacing a Church seat, it can be replaced with any brand available at the moment.

Toilet seat vocabulary:

  • Rim or ring - The open seat.
  • Cover - The lid/cover/top that closes over the rim.
  • Bumpers: The spacers on the bottom of the rim and the cover.
  • Hinges - The mechanical part that raises and lowers the rim and cover.
  • Bolts - The threaded posts connecting the hinges to the toilet.
  • Nuts - The nuts and washers that attach to the bolts.
  • Bolt-spread - The distance between bolt holes on the toilet measured from center-to-center. Aka hinge-spread.
  • A toilet seat is comprised of the rim for seating and the cover that closes over it. Mounting hardware (bolts & nuts) are included with the seat.

Normal seat: Here are the three criteria which distinguish a normal-style toilet seat:

  1. The seat hinges are 5-1/2" apart from center-to-center.
  2. The hinges mount down vertically, not back horizontally.
  3. The shape of the front of the seat is curved; not angular, square or squared-off.

If a toilet seat is different from any one of these features, it is special, unique and proprietary.

Sizes: Normal-style toilet seats come in two bowl length sizes: Round or elongated. Round is also called "regular" and "plain."* Elongated is also called "extended." Some consumers say "oblong." Although round and elongated are shapes, the shapes refer to the front-half of the seat. The difference of two inches is key. When measuring to determine the size, measure the porcelain toilet bowl, not the seat itself.

* Kohler says "plain" which is the same as  round. Their model number suffixes are PB - Plain Bowl and EB - Elongated Bowl.

Measure the toilet bowl, not the seat.

Dimensions: The widths of seats are not made in dimensional choices. Though there may be some fractional variance between wood vs. plastic or different brands and models.

Materials: Toilet seats are made primarily of two material types:

  1. Enameled wood.
  2. Solid plastic.

Enameled wood is a composition of tiny wood shavings (almost saw dust) which are mixed with resin and compression-molded to form a solid material. The "wood" is then enamel painted. Since around 2000, MDF, Medium Density Fiberboard, has also been used to make "wood" seats.

Plastic seats begin as a molten material which is injected into a mold to form the product. The material and color are solid-through.

Brands: Toilet seats are to toilets like tires are to cars. That is, there can be a Ford or a Chevy car. One might come with Firestone tires, the other might come with Goodyear tires. When the tires wear out, they might get replaced with Michelin or Bridgestone. Any of the tire brands will fit each of the cars. There are many brands of toilet seats and they can go on each brand of toilets. Exception: Sometimes major toilet brands will have toilet seats private-labeled to match their product brand. E,g., American Standard or Kohler.

Frequently answered questions:

Q: Aren't wood seats better than plastic?

A: Not necessarily. "Wood" seats, aka enameled wood, aka composition wood, aka molded composition are not made of beefy lumber. They are made of sawdust and resin which are compression molded. ...Much like particle-board. The compressed sawdust is then painted. They look thicker and stronger and feel heavier because they must be two-to-three times thicker than plastic to achieve the same strength. The paint color is very thin compared to plastic seats where the color is solid through. (Drill a hole through each to see.) Bathroom humidity, moisture from bowl water, acid vapors from urine, urine splashing, and the chemicals from cleaning agents* will eventually cause the paint on wooden seats to fail. Plastic seats are not susceptible to this failure. The paint on wooden seats can chip. Plastic seats won't chip. The bumpers on wood seats are screwed, nailed, or tacked onto the seat - they can fall off over time. The bumpers on our plastic seats are molded-in - they are integral and cannot come off. If you are replacing a wood seat now, it is probably for one of these reasons. In the case of toilet seats, plastic is better than "wood" in our opinion.

* Clean with warm soapy water.

Q: What is the cover for?

A: A toilet seat cover is for two things: Cosmetics - To block the open toilet bowl from view and Function - to protect from dropping things into the toilet bowl.

Tip: Do not sit on the cover when closed. It wasn't designed for that weight. Not a chair.


Q: Do you have repair parts* for toilet seats?

A: No. There are too many brands, models and ages of seats to keep track of. Most manufacturers don't support this. Hardware stores carry some generic/universal parts - maybe you'll get lucky. Some manufacturers carry some parts for some of their seats. Contact their support.

* Hinges, bolts, nuts, pins, screw-cover caps, bumpers.

Slow-close hinges are a recent advancement/enhancement for toilet seats. This appears by various names such as slow-close, whisper-close, silent-close, easy-close. The feature is a winding mechanism when the seat is raised.  This creates resistance when the seat is lowered. The function is the seat lowering itself without dropping. The benefit is lowering the seat and closing the cover hands-free. Plus there is no slamming if the seat is dropped to close. This feature is mostly on plastic seats.

Quick-release hinges are a concealed feature that allows the hinges to disconnect from the mounting bolts by hand - no tools. The function is the ability to remove the seat from the toilet. The benefit is the ease of cleaning around the mounting area.

Reasons for new toilet seats:

  • Mechanical failure -The hinges are broken.
  • Structural failure - The rim is cracked.
  • Function - The bumpers are worn, loose, or missing.
  • Cosmetic - The finish and color are worn away. (Enameled wood seats.) The chrome or brass hinges are tarnished or corroded.
  • Hygiene - Install new seats to replace used from prior owner.

Warning: Loose toilet seats can contribute to a slip-and-fall. Missing bumpers may cause the seat to be uneven and contribute a slip-and-fall. Missing bumpers may cause weight distribution to be incorrect. This stress may cause the rim to crack or the hinges to breakaway.

Not covered here are commercial, institutional, medic-aid and bidet toilet seats.