What Size Flapper Do I Need?

You discovered there are some differences in flush valve systems and that toilet sizes can vary. An easy reference is to look at the size of the flush valve drain opening at the bottom of the tank. 

If it’s about the size of an orange or baseball, you need a 2-inch seal. If it looks more like the size of a grapefruit or softball, you need a large 3-inch seal. You can also measure the flush valve opening to determine what toilet flapper size you need. 

Does this describe your toilet issue?

Step 1: Find the Correct Sized Flapper

Toilets and their flush valve systems come in different sizes and shapes. Flappers are available in two sizes: standard two-inch, and large three-inch. Most toilets use the standard two-inch flapper, but large three-inch flappers have become popular recently. 


To quickly determine your toilet's flapper size, look at the flush valve drain opening at the bottom of your tank. If your flapper is about the size of a baseball or an orange, you need a two-inch flapper. You need a three-inch flapper if it's more like a softball or grapefruit.

Flapper Sizes Guide

Step 2: How to Install a Toilet Flapper

  1. Shut off the water supply to your toilet and flush until the water is fully drained.
  2. Drain any remaining water from the tank by holding down the flush handle.
  3. Disconnect the flapper chain from the flush lever and remove the old flapper.
  4. Clean the flush valve opening and surrounding area to remove mineral deposits or debris.
  5. Install the new flapper, making sure it sits evenly and creates a proper seal.
  6. Reconnect the flapper chain to the flush lever, leaving a little slack for smooth movement.
  7. Turn on the water supply to refill the tank and check if the flapper seals tightly.

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