2″ Vs. 3″ Toilet Flapper: The Differences!

Last Updated on September 22, 2022 by Alex Cubias

It is important that you purchase the right size replacement for the parts of your toilet. However, there are often more options, and you can’t be sure what kind you need to get. Does your toilet need a 2″ flapper and flush valve or a 3″ flapper and flush valve?

A toilet with a 2″ drain in the tank will need a 2″ flapper and flush valve, and a toilet with a 3″ drain will need a 3″ flapper and flush valve. Toilets manufactured after 2005 are more likely to have a 3″ drain, and toilets that use more gallons of water per flush have larger drains.

There are a couple of different ways to determine what size of flapper will fit into your drain, and it may be good to know how the size affects the way your toilet flushes. It is also important to know what type of flapper and flush valve you should go with.

Determining the Size You Need

Different toilets are going to need different sizes of flappers and flush valves. It isn’t something you can randomly choose, so make sure you know what kind to get before you go to the store to buy a replacement or order one online. You may end up with a flapper or flush valve that won’t fit your toilet.

The size of the flapper and flush valve that you need depends on the drain in the tank. This drain is where the water from the tank flows into the toilet bowl when the toilet is flushed. A flapper is designed to block the water from draining out of the tank, while the flush valve releases the water into the bowl when the toilet is flushed.

A certain-sized drain is going to need a certain-sized flapper to be able to block it off correctly. A flapper that is too small will not be able to block the entire thing off, and a flapper that is too large won’t fit into the drain. The flapper and the flush valve also need to be the same size so that the flapper can regulate the flush valve properly.

To figure out what size flapper and/or flush valve to purchase, you will need to measure one of the components of the toilet. Before measuring anything, you should turn off the water to the toilet and empty the tank.

One component you can measure is the drain. If it is about two inches in diameter, you will need a two-inch flapper/flush valve. If it is three inches in diameter, you will need a three-inch one.

You can also measure the flapper that is currently in your toilet. Make sure not to measure the diameter of the whole flapper but rather the diameter of the part that goes into the drain. The whole flapper will be longer than 2″ for a 2″ drain or 3″ for a 3″ drain to keep it from falling into the drain.

Finally, you can measure the diameter of the flush valve that is currently in your toilet. Try to measure the actual flush valve and not the overflow tube, which is a part on top of the flush valve that is often wider.

If you aren’t able to measure any of these components, you can eyeball it. If the flapper, drain, and flush valve opening are the size of a baseball or orange, it is probably a two-inch drain. If it is the size of a softball or grapefruit, it is probably three inches.

You can also figure it out based on the year that your toilet was manufactured. Most toilets made after 2005 have three-inch drains, while most of those made before 2005 have two-inch drains.

Toilets with a higher number of gallons per flush have a larger drain and a larger flapper and flush valve. Larger drains will release more water and have faster flushes. Toilets with 1.6 or 1.28 gallons per flush tend to have 3″ flapper valves.


Types of Flappers

There aren’t just different sizes of flappers, but different types of each too. There are five different types of flappers, and each does different things. To determine which of these types to buy, look at the flapper that is already in your toilet, figure out what kind it is, and purchase the same kind. The different types of flappers work on different types of toilets.


The first type of flapper is a seat disk tank flapper. This is the oldest kind of flapper. They tend to be inefficient and complicated to use. They look like rubber disks with a wagon wheel pattern of ridges.

The second type of flapper is a tank ball toilet flapper. They tend to be shaped like large rubber tops. These types usually act as a float-ball as well as a flapper. The flapper will fill with water and sink to the bottom, but it has many opportunities for failure and often won’t work properly, so these are not used much either.

The third type of flapper is a non-adjustable rubber tank flapper. This is the most commonly used type these days. It is a piece of rubber connected to the flush valve with a hinge. The water fills the flapper until it closes it automatically at the right time.

The fourth type is a rubber tank flapper with a floater. This is one of the ways to use a rubber tank flapper that is adjustable so you can choose the amount of water in a flush. It has a float attached to it which stays on top of the water. You can move the floater on the chain, which will change how much water is released.

The final type of flapper is a rubber tank flapper with a control dial. This is another way for a rubber tank flapper to be adjustable. There is a dial built into the flapper that can change the amount of water released in a flush.