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What Size Toilet Flapper Do I Need? Things to Know!

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Written By Paulk Webb
Fact checked by Freddie J. Hagopian


what size toilet flapper do i need

Are all toilet flappers the same? What size toilet flapper do I need? This is something that you have to think about when you purchase a toilet. The flapper inside the water tank is the seal that prevents water from coming out. It will allow the water to get into the bowl when you flush the toilet. Furthermore, flappers are the parts that prevent leakage.

You can expect that the mentioned tasks are done, regardless of toilet flapper sizes. Still, you need to get the one that suits your toilet. It’s a must as it falls apart over time. Replacement is necessary every 5 to 7 years. To choose the right toilet flapper, let this article guide you.

Types of Toilet Flappers


The toilet flapper types depend on the amount of water used per flush. Based on the changes in the toilet’s water consumption, flappers are also modified. Toilets used to require 5 gallons per flush then it was lowered to 3.5 gallons. For the sake of conserving water, new technology was able to produce toilets that operate with 1.6, 1.28, or even lower GPFs.

Despite the lower water consumption, modern toilets have great efficiency. While the old toilets have a 2-inch valve, the newer models have 3 inches. The size of the toilet flapper depends on the size of the valve. Bigger valves of modern toilets mean more water can be released to create a surge of power.

Even with less water, the waste can go down with the strong, siphonic effect. This is why in 2 in vs 3 in toilet flapper, the latter wins. You may think that a 3-inch flapper is big enough but there’s a bigger American Standard flapper size that is 3 inches.

How to Know if the Toilet Flapper is for a 2-inch or 3-inch Valve?

One way to know is by comparing the valve’s opening to a softball or baseball. A 2-inch flapper is similar to a baseball or orange. The 3-inch flapper is the same size as the softball or grapefruit.

Another method is to take off the old flapper and bring it to the local home improvement shop. The specialist will not bother measuring it as this person knows about toilet bowl flapper sizes just by looking at them.

To find it yourself you can measure the toilet flapper through these steps.

  • Step 1: Turn off the toilet’s water line.
  • Step 2: Remove the lid of the water tank.
  • Step 3: Flush the toilet so you can hold down the flush.
  • Step 4: You have to prepare the measuring tape ahead so you can grab it and measure the flapper after removing it from the valve.
  • Step 5: After getting the numbers, turn the water valve on for the refill of the water tank.

Different Flappers for Toilets


Rubber – It’s the common type of flapper found in recent toilet models. It has a simple cap that is linked to the overflow pipe. The mechanism of this flapper can be compared to the tank ball flapper. During flushing, a chain lifts the flapper. The chain also guides the flapper back into its designated place after the flushing is done.

Even though you call it a rubber flapper, it’s not entirely made of the said material. If you inspect it, you’ll find that the rubber is only on the edges to create a tight seal on the overflow pipe. Its reliability made this flapper common and popular.

Since it works similarly with ball flappers, it has the same downside: not having the right length of chain. An incorrect amount of water will come in and out of the tank and this can lead to leakage.

Tank Ball – This flapper is situated on top of the overflow pipe. There’s a chain that lifts the ball every time you flush the toilet. To allow the right amount of water to drip into the bowl, the correct length of the chain is essential. There are consequences if the chain is not of the right length. The ball will fail to seal the valve and a lot of water will be wasted in every flush.

Seat Disk – This is the oldest type of toilet flapper that features a small, round disk above the overflow pipe. It opens the said pipe when flushing is done. There’s a water reservoir that holds this flapper when the toilet is flushing to give way to the water. Flushing empties the reservoir so the flapper needs some moments before it closes.

Downsides are expected from this oldest flapper. It’s large so it takes a lot of space in the water tank, which is irrelevant to the function. Replacing this flapper is quite challenging. You will need to look high and low for it and when you have it, the replacement process will not be easy.

Sum Up

What size toilet flapper do I need? This question has been answered by this article. The old toilets typically have a 2-inch flapper while it’s 3 inches for new toilet models. You may also find modern and upgraded toilets with the 4-inch flapper. The bigger the flapper, the more powerful the flush is even though less water is used. The size of the flapper matters as it’s responsible for dropping the water into the bowl.

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