Toilet Rough-In Dimensions (with Drawings)

Perhaps you are renovating a house or doing a major bathroom makeover. For a bathroom, the toilet and its placement are crucial considerations, as is knowing the rough dimensions of the toilet. Make your first priority knowing where your toilet will be in the bathroom and how much space it will take up.

The standard shell dimensions for toilets are 10″, 12″ and 14″, 12″, which are most common in newer homes and buildings. The rough measurement is the distance from the adjacent wall of the toilet to the center of the toilet’s screws. The shell dimensions are the most important indicator of whether a new toilet fits into a bathroom or not.

Other fixtures in your bathroom may be somewhat adjustable in their placement. The toilet is not one of them, so it is very important that you know its dimensions and approximate dimensions. Here we help you get all the information you need to have your toilet in the right place.

Standard toilet raw dimensions

The shell of a toilet represents the space between the wall behind the toilet and the center of the toilet drain. This measurement is the most important indicator of toilet placement. The toilet faucet needs to be connected to the drain while being mounted in front of the adjacent wall.

The standard dimensions for a shell toilet are 10″, 12″, and 14″. The most common of these is 12″. Rough-ins that are 10″ or 14″ are usually only found in older homes.

Taking measurements for a rough toilet

The shell of a toilet is the distance from the wall behind the toilet to the center of the toilet’s screws. If the measurement is not exactly 10″, 12″ or 14″, round down to the nearest standard measurement.

Standard toilets often only have two bars, but there are also some with four. If you want to get the raw value of a four-bolt toilet, measure to the center of the rear bolts.

When taking measurements on the wall behind the toilet, be sure to measure the actual wall. If there is a tile border or baseboard at the bottom of the wall, measure from the drywall behind it.

General dimensions of the toilet

Knowing the approximate dimensions of your toilet is only part of the bathroom installation process. The next part is to know the overall dimensions of a toilet.

Standard toilets range in depth from 22 inches to 29 inches from the front of the bowl to the back of the tank. The tank is the widest part of the toilet, measuring 16” – 20” wide. The standard height of a toilet ranges from 27″ to 32″.

Toilet tank dimensions

Toilet tanks can be between 16″ and 20″ long, 13″–14″ high and about 8″ wide. They don’t necessarily change their dimensions in relation to their gallon capacity.

The standard length measurement for a small toilet tank is 15 ⅛”. The standard length for a large tank is 16 ¾” – 18”. The lid can add 1″-2″ height to the tank.

Dimensions of the toilet seat

Toilet seats have length and width dimensions similar to the toilet bowl, which varies with different toilet types. However, they are typically 1 inch thick. The lids are approximately 1.25 inches thick, so the lid and seat together are 2.25 inches tall.

If you want to learn more about toilet seat materials, you can read about it here.

Dimensions of the toilet bowl

The height of the toilet bowl is a measurement that varies with different types of toilets. The standard height from the floor to the edge of the pool (excluding the seat) is 14.5 inches. However, some newer models have a height of 16 ⅛” to the rim.

Oblong vs. round toilet bowl dimensions

Elongated toilet bowls are oval rather than circular. You’re more likely to find them in newer homes, and people often mistake them for being more modern. They are larger than their round toilet bowl counterparts, giving the user more seating space.

Round toilet bowls have a round shape and are mostly only found in older houses. Most people prefer oblong toilets for comfort and appearance, but round toilets take up less space. If your bathroom is short on space, a round toilet can be a good option for you.

Typically there is a 2 inch difference in length between a round toilet bowl and an oblong toilet bowl. The dimensions of the toilet may change depending on the manufacturer, but the 2-inch difference remains the same.

Oblong toilet bowls are approximately 18.5 inches from the screw to the front of the bowl. Round toilet bowls are generally 16.5 inches from the screw to the front of the bowl. However, be sure to check the specs of the fixture to get the exact measurement.

If you want to replace a round toilet with an elongated one, you can read about it here.

Types of toilets and their approximate dimensions

Rough dimensions of the toilet with rear drain

Toilets with a back exit that opens into the wall instead of opening into the floor are referred to as back exit toilets. These are in-wall rather than in-ground, but are not the same as wall-mounted toilets. Find the dimensions of a rear drain toilet by measuring from the bottom to the center of the outlet pipe.

Rough dimensions for rear drain toilets are 4″-7.5″ from finished floor to center of drain. Other than that, the dimensions for rear drain toilets are similar to those for floor mounted toilets.

Wall mounted toilet dimensions

Wall mounted toilets are rare but are growing in popularity. The bowl of a wall-mounted toilet is the only part of the faucet that is visible. The tank and output lines are hidden behind the wall.

Because of their hidden tank and plumbing, wall-mounted toilets are significantly smaller in overall size compared to other toilets. They can be an aesthetic toilet option when designing a bathroom with limited space. The shell of a wall-hung toilet must be designed to fit into the adjacent wall.

The height dimensions of the wall mounted toilets are 15″-19″ from the finished floor to the top of the rim of the basin. If you included the seat and lid, this measurement is 18″-22″.

The depth of a wall mounted toilet from the outside of the rim to the wall is about 21 inches. The width of the toilet is 14″-15″ in diameter.

Corner toilet raw dimensions

Corner toilets are another space-saving alternative to traditional toilets. The bowl and plumbing dimensions are the same as a traditional toilet. The tank has a different shape but similar width and height dimensions to traditional tanks.

The approximate dimensions for a corner toilet are the same in measurements, but you will find them different. On both walls, measure the rough distance from the inside of the corner to the outside. Then measure from that point on the wall to the bathroom floor.

You are essentially drawing a square. The rough position will be where these two lines meet on your bathroom floor.

Toilet clearance dimensions

Knowing that your toilet will physically fit within the rough construction allowance and the space available is the first step. The second step is to make sure he has adequate space around him. Clearances allow for compliance and proper use of all fixtures in your bathroom.

Side panels and adjacent vanities

A distance of at least 15 inches must be maintained from the center of the toilet to the nearest side wall, vanity or tub. Note that the distance is taken from the dead center of the toilet, not from the outside of the tank or bowl. However, you should measure to the nearest edge of the vanity or tub, not the center.

Neighboring fixtures

The most common ancillary feature of a toilet is a sink. If it is a freestanding sink, it will have a different spacing than a vanity top. There should be at least 30 inches of space between the center of the toilet and the center of the freestanding sink.

Fittings in front of the toilet

The clearance for fixtures in front of the toilet should generally be at least 24 inches. If you are designing a bathroom for a makeover, this number will change depending on which code you are under. The IRC needs 21 inches of clearance while the UPC needs 24 inches.

toilet paper holder

There is no set approval for a toilet paper holder. However, it is recommended that they be 30 inches off the ground with 12 inches of space in front of them.

in summary

Before you take any further steps in designing or renovating your bathroom, it is important that you know the dimensions of your toilet. The rough dimensions of the toilet are crucial to knowing how much space you have available in your bathroom.

Typically, a standard toilet is sized 10″, 12″, or 14″. A 12″ rough-in is the most common rough gauge, but 10″ and 14″ can be found in older homes. You can find the rough gauge by Measure from the center of the toilet screws to the finished wall.

Along with this measurement, you should also know what type of toilet you want and its overall dimensions. Also note the clearances for your toilet to ensure you are following code requirements. We hope this helps you with your bathroom design and toilet selection so you can find the best fit for your bathroom.

Stacy Randall

Stacy Randall is a NOLA wife, mother and freelance writer who has always had a passion for DIY projects, home organization and room beautification. Together with her husband, she has spent the last few years lovingly renovating her grandparents’ former house and making it her own, while learning a lot about life in the process.