Bathtub Drain Flange Sizes: Complete Size Guide

Bathtub Drain Flange Sizes

Bathtub drain flange is usually something most of us don’t pay attention to.

However, while purchasing a new stopper or replacing the flange, you might have no other option but to find out about the bathtub drain flange sizes. 

Only once you know the exact size can you buy a stopper or replace the same.

The question then arises, what are the usual bathtub drain flange sizes?

Today I will answer that question and help you understand how to determine the size accurately. Before that, it is time to understand exactly which part is referred to as the flange in the bathtub.

What Is A Bathtub Drain flange?

The bathtub drain flange is the part on top of the drain opening that is directly visible to your eye. It also goes by the name of drain basket or drain body. According to your tub type, the finish of the bathtub drain flange might be different. Also, it becomes critical if you plan on using the bathtub stopper.

The size of the flange will determine the type of stopper you use. Apart from that, the size of the flange also becomes essential when you want to replace them.

Just like any other part of the bathtub, it might also suffer from wear and tear, so it is essential to know the sizes.

What Are The Usual Bathtub Drain Flange Sizes?

The usual drain flange size can vary between 1.2 to 2 inches. These are the two variants usually available. I will discuss the details of these below to help you understand in which case a bathtub uses either.

1. 1.5" Drain Flange

Usually, if you have a normal tub without a shower, you will have a 1.5-inch drain flange. This is the same as the flange in your kitchen sink.

For a long time, most manufacturers have been sticking to their specifications. When the drain flange is of the same size, it becomes easy for you to connect it to the pipe to replace it if required. However, the drainage pipe can still be larger than 1.5 inches.

2. 2" Drain Flange

If you have a shower top, the drain flange can be 2 inches. The reason why a shower tub requires a larger one is because of the plumbing code.

The code states that a bathtub can drain slowly; therefore, a 1.5-inch flange is more than enough for the same.

On the other hand, when using a shower, you might need faster drainage as water accumulation in the tub is not required. In this case, the 2-inch is the better choice.

These are the two usual sizes of the bathtub drain flange.

Of course, it is not easy to merely judge with the naked eye. That is why; I will share a step-by-step procedure below to measure the flange size.

How To Measure Tub Drain Size?

To measure the tub drain size, you must remove the flange from the bathtub. The procedure below lets you know how to do so.

Step 1: Remove The Flange Using A Drain Key

To accurately measure the flange, you will have to remove it. For the same, use a drain key or a small dumbbell. Enter either one of them into the opening and rotate counterclockwise. You have to continue doing the same until the flange comes up and is released from the rest of the assembly.

After it comes out, remove the dumbbell or drain key from it.

Step 2: Measure The Opening from One End to Another

Once you have access to the flange, take a usual measuring tape and measure it from one end to another. That is, measure the diameter.

It will either be 1.5 inches or 2 inches.

Step 3: Do Not Forget Vertical Measurement

Until now, I have only been focusing on the diameter of the drain flange. However, the drain flange’s length or the vertical size can vary from one option to another. That is why, when you extract it, it is crucial to measure its vertical dimension. Only then can you buy the one which fits your bathtub accurately.

Step 4: Put The Flange Back

Once the measurement is done, reinsert it if you do not want to replace it immediately. To do so, use the same drain key or a small dumbbell to put it back into the drain and rotate it clockwise.

Using these four simple steps, you can measure the flange and buy a replacement so that your bathtub’s drainage system starts functioning accurately again.

What Is Considered to Be An Oversized Tub Drain Flange?

If you have a tub dating back from the 1980s or even older, the flange size will be different.

Usually, anything over 2 inches is generally considered an oversized tub drain flange. In the older tubs, you will even find 3-inch ones.

The question which then arises is, can you replace those?

Unfortunately, the answer is no in most cases. The oversized flange is not available these days.

Wondering what you should do in that case?

There are essentially two solutions:

1. Refinish

You can refinish the entire bathtub, which will ensure that you can reduce the size of the flange, and therefore you can install the current 1.5 or 2-inch ones into it.

2. Scrap The Bathtub

Let’s accept that tubs dating back to the 1980s might be too old to use anymore. That is why you can think about scraping the bathtub.

Frequently Asked Questions

The usual drain size of an old bathtub is usually 1.5 inches. However, if you have an antique tub dating back to the 1980s, the size can be as big as 3 inches.

The standard bathtub drain holes are of the same size, 1.5 inches. The pipe is also of the same. In the case of a shower bathtub, it increases to 2 inches.

Final Words

Next time you want to change the bathtub drain flange, just refer to the bathtub drain flange sizes above. Using the guide, you can replace it easily. In case you want to measure it, the guide above details the step-by-step procedure to do so.

Spread the love

Leave a Comment

Your email address will not be published.