offset toilet flange sizes

What Is The Standard Size Offset Toilet Flange

Sometimes your drainpipe may not be installed directly on the toilet’s location, which makes toilet installation problematic. This is where an offset toilet flange comes to the rescue since it’s designed for drainpipes that have non-standard rough-ins. 

You can install an offset toilet flange in various orientations, depending on the distance you want your toilet to be from the bathroom wall. It lets you shift your toilet by approximately 2 inches backways, forward, or sideways.

Therefore, don’t fret if the toilet plumbing in your home wasn’t properly installed because you don’t have to do the strenuous work of redoing it. An offset toilet flange offers a convenient solution; you just need to find the right size.

This post explores the different sizes of offset toilet flanges.

Offset Toilet Flange Sizes Explained

Offset toilet flanges come in various sizes, but size 2 inches is the most common because it fits most standard drain pipes. The appropriate offset toilet flange size for you will depend on your toilet opening. 

Basically, a 2-inch toilet opening requires a 2-inch offset toilet flange. The other sizes are:

3-Inch Offset Toilet Flange

The top and the bottom diameters of a 3-inch offset toilet flange are equal, making installation pretty simple. However, you can only install this flange on a drainpipe with a 3-inch diameter or 3-inch bend.

If you discover that the drainpipe isn’t 3 inches after you’ve started installing this offset flange, you will need to install a reducing bushing. However, remember that doing so raises the flange’s position unnaturally, and that might affect your toilet’s plumbing alignment. 

4-Inch Offset Toilet Flange

You can also get a 4-inch offset toilet flange, but this size is uncommon and nearly out of use. These flanges require wider drainpipes which rarely come by anymore, especially in modern houses unless you have an old house. 

4 x 3 Offset Toilet Flange

This flange has a top diameter of 4-inches while the bottom is 3 inches, which means your drainpipe needs to be 3 inches to install this flange. This closet flange is your best option if you are unsure about your toilet’s drain pipe size. 

Read also 3 ways to fix toilet flange below tile

Offset Toilet Flange Types

Offset toilet flanges are made of either metal or plastic, and each material has its benefits and shortcomings.

a) Plastic

Plastic closet flanges are popular because they provide multiple benefits. They are commonly found in most buildings, from residential buildings and houses to commercial real estate. 

PVC flanges are lightweight, rust-resistant, very affordable, waterproof, easy to install, and durable (they are made to be long-lasting).

However, you must be careful when installing as you must ensure you do a perfect job. A plastic flange could break sooner if installed on an uneven bathroom floor because PVC elements cannot withstand massive pressure when sealed imperfectly.

You can go with ABS plastic offset flange, which is stronger and lighter than PVC. However, it will cost you more.

b) Metal

Metallic offset toilet flanges are your best option if you are looking for a durable option, but they will cost you more than a plastic one. The metals used to make flanges include stainless steel, brass, copper, aluminium, and cast iron.

Brass was a popular material in the past, but not anymore because it is susceptible to oxidation which happens when flanges are exposed to air and moisture. On the upside, this metal is highly durable, malleable, robust, heat resistant, and stable. 

Stainless-steel toilet flanges will serve for many years, even decades, since they are robust. On the other hand, copper closet flanges are durable, corrosion-resistant, and fend off bacteria, viruses, and fungi. 

Many people usually go with soft copper since it’s easy to install and flexible. You will require an elbow-shaped joint on the toilet outlet if you go with rigid copper.

Cast iron makes durable, wear-resistant, and tough flanges which are also resistant to moisture, air, and water. However, you can only use this flange on iron drain pipes. While aluminium toilet flanges aren’t common, this material is lightweight, durable, and resistant to corrosion. 

Manufacturers don’t usually make aluminium toilet flanges but instead add traces of manganese, copper, and zinc to make them sturdier and stronger. 

Read also Offset toilet flange problems

The Best Offset Toilet Flanges In Different Sizes

Now that you know the sizes and materials that offset toilet flanges come in let’s look at some of the best options offered in the market. 

1. Sioux Chief Manufacturing 889-GPOM

This offset toilet flange is made of PVC with a stainless steel ring and designed to fit a 4-inch drainpipe. The exact dimensions of this product are 4 x 3 x 3 inches, and it comes with a rubber gasket.

You can buy it in a package containing one flange or opt for a set or 2, 3, or 4.  

2. Oatey 43500 Level-Fit Offset Toilet Flange, 3 X 4 in, Abs Plastic, 3-Inch or 4-Inch

You can use this offset toilet flange to fit your toilet on a schedule 40  DWV pipe with an inside diameter of 4 inches or over 3 inches. Oatey 43500 is ABS plastic made with a metal ring to give the flange resistance to cracking, added strength, and it can be rotated to facilitate the correct alignment of screws and bolts.

It has a 2-inch offset that provides margin or error when aligning the flange or drainpipe. Moreover, this flange protects the tub against damage during house construction.

In addition, it features a high-impact, heavy, semi-flexible plastic that has deep-fluted sidewalls. It also has a non-skid foam pad for preventing dents and scratches on tub finish and shock absorption.

3. Oatey 43501 3 in. or 4 in. Level Fit White Metal Ring, No Test Cap PVC Offset Closet Flange, 3-4”

It’s made from highly durable, semi-flexible plastic polymer and has a built-in cut-out that fits up to Schedule 40 drain of 2-inches. This comes in sizes 3 to 4 inches and 1-inch thickness. 

This United States-made offset toilet flange provides clean, economical, and quick installation. You can easily connect a trap to your drain system because it lets you create a clean cavity in a slab of concrete. 

Read also How to fix toilet flange 1/2 above floor

FAQ on Offset Toilet Flange Sizes

1. Are Offset Flanges Illegal?

The legality of offset flanges varies based on the area code, so check your area’s plumbing codes to ensure it’s legal to use them before getting one and installing it. 

2. Are Offset Toilet Flanges Bad?

Offset toilet flanges are handy components, but you may encounter issues if you mishandle them. For instance, it can cause leaks if you don’t seal it well or clogs if positioned poorly.


Since offset toilet flange sizes vary, knowing the exact size you need will ensure you have the perfect fitting. Moreover, make sure to align the flange to the drainpipe properly and tighten the bolts to avoid leakages. 

Read also How to fix toilet flange too close wall

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