Toilet rough in is the distance from the finished wall behind the toilet to the center of the floor drain (the closet flange). In most homes it is 12 in, but 10 in and 14 in turn up in older houses and tight bathrooms. Measure before you order: a toilet built for a bigger rough in than you have will not fit, while one built for a smaller rough in fits with a gap behind the tank.
What toilet rough in means
The rough in is set when the drain pipe is installed. The toilet outlet seals onto the closet flange on top of that pipe, and the outlet position is fixed inside the china, so every floor mounted toilet is built for one rough in. The new toilet has to match the old pipe, not the other way around.
Two details trip people up: the measurement starts at the finished wall surface (drywall, tile or panel), not the baseboard, and it ends at the center of the drain, not its near edge. Ferguson’s buying guide, How to Choose a Toilet, describes it the same way and notes the usual 12 in figure, with 10 in and 14 in also possible.
How to measure toilet rough in
With a toilet already installed
- Find the two closet bolts that hold the toilet to the floor, usually under plastic caps on each side of the base, and pop the caps off. The bolts sit on the flange, roughly in line with the center of the drain.
- Hook a tape measure on the finished wall behind the toilet, above the baseboard, and run it straight out to the center of one bolt.
- Repeat on the other bolt. The two readings should be close; use the average.
With the toilet removed
- Measure from the finished wall to the center of the drain opening, not to the rim of the flange.
- If the wall is going to get new tile or a thicker panel, subtract that thickness, because it moves the finished wall closer to the drain.
Reading the result
Readings rarely land on a whole number. A sensible rule: never buy a toilet with a rough in larger than what you measured unless the spec sheet shows the tank still clears the wall. A reading of 12 1/4 in points to a 12 in toilet; 11 1/2 in calls for a spec sheet check or a plumber before ordering a 12 in model.
12 inch rough in: the standard
Most new construction uses a 12 in rough in, and it is the size listed on almost every toilet in our catalog, so your choices are wide open. Our one piece vs two piece toilet guide covers style choices.
10 inch rough in and 14 inch rough in
A 10 in rough in is common in older homes and small bathrooms where the drain sits close to the wall. A 14 in rough in also shows up in older houses. Fewer models are made for either size. When the sizes do not match:
- 12 in toilet on a 10 in rough in: it does not fit. The tank hits the wall before the outlet lines up with the drain.
- 12 in toilet on a 14 in rough in: it fits, but leaves about a 2 in gap between the tank and the wall. The bowl also sits farther into the room, which can eat into front clearance.
Offset flanges and their limits
An offset closet flange moves the toilet’s drain connection a short distance off the center of the pipe, so a 12 in toilet can work over a drain that measures a little short or long. The limits:
- It only moves the outlet a short way, so it cannot turn a 10 in rough in into a true 12 in.
- It narrows the flow path at the bend, and some local codes restrict where it can be used.
- It usually needs the floor opened enough to seat the new flange on the pipe, so it is a plumbing job, not a quick swap.
A toilet made for your actual rough in is usually simpler. A licensed plumber and your local code have the final word on any flange or drain change.
Rear outlet and wall hung toilet rough in
A rear outlet toilet drains through the wall instead of the floor. A wall hung toilet is the most common example: the bowl bolts to an in-wall carrier that holds a concealed tank, and the drain runs horizontally into the wall. For these, the floor measurement from the wall does not apply. What matters is the height of the drain outlet above the finished floor and the carrier’s fit inside the wall framing.
The WOODBRIDGE compact wall hung toilet with bidet lists its rough in as “Wall Mounted.” Its listing says the carrier suits residential 2×4 stud walls, finished walls up to 3.5 in thick, and a frame height adjustable from 47 to 55 in. The separate WOODBRIDGE in-wall tank carrier includes rough in material and mounting hardware, and its listing states it supports up to 500 lbs. Neither listing gives a drain outlet height, so get that from the installation manual before framing. Our wall hung toilet guide goes deeper on carriers and mounting height.
Side and front clearance
Rough in sets where the toilet sits front to back; you also need room on each side and in front of the bowl. Code minimums vary by jurisdiction, so check your local code before planning a layout. If you are fitting a vanity next to the toilet, our bathroom vanity sizes guide helps with the space around it.
Toilets we carry that list a rough in
Only models whose product page states a rough in are listed. Prices are current store prices; this is a spec based buyer guide, not a hands on review.
| Toilet | Type | Rough in (as listed) | Price |
|---|---|---|---|
| ANZZI Odin T1-AZ056 | One piece, dual flush, 1.6 GPF | Standard 12 in | $374.39 |
| WOODBRIDGE T-0032-CH | One piece, dual flush, skirted | Standard 12 in | $467.00 |
| WOODBRIDGE EBT700 | One piece smart bidet toilet | Standard 12 in | $1,055.00 |
| WOODBRIDGE LT610 | One piece smart bidet toilet | Standard 12 in | $1,439.00 |
| WoodBridge B0931S | Smart bidet toilet, S-trap | 12 in (305 mm) | $3,120.00 |
| WOODBRIDGE compact wall hung toilet (LT611) | Wall hung with in-wall carrier | Wall Mounted | $1,823.00 |
| WOODBRIDGE in-wall tank carrier (WHTA001) | Carrier only, for wall hung bowls | Rough in material included | $899.00 |
Every floor mounted model on this list is built for a 12 in rough in. If you measured 10 in or 14 in, call us before you order and we will check current options with you. Thinking about a smart model? Our smart toilet vs bidet seat comparison covers power and water hookups. You can also browse all WoodBridge toilets and bidets.
Frequently asked questions
How do I measure toilet rough in?
Measure from the finished wall, above the baseboard, to the center of the closet bolts, or to the center of the drain if the toilet is removed.
Is a 12 inch rough in standard?
Yes. It is the most common size today, and every floor mounted model in our table above lists it.
Can I put a 12 inch rough in toilet on a 10 inch rough in?
Usually not. The tank will hit the wall before the outlet lines up with the drain. Look for a toilet made for a 10 inch rough in, or ask a licensed plumber about moving the drain.
Can I install a 12 inch toilet on a 14 inch rough in?
It fits, but leaves about a 2 inch gap behind the tank and pushes the bowl farther into the room.
Does a rear outlet or wall hung toilet have a rough in?
Not in the floor sense. A rear outlet (wall hung) toilet drains through the wall, so the key figures are drain outlet height and carrier fit, found in the installation manual.
Need help matching a toilet to your rough in? Call us at 866-777-2590, Mon-Fri 9AM-6PM PST. Orders of $999 or more ship with free freight shipping, and orders below that ship for a flat $200. Returns follow our return and refund policy. For any drain, flange or carrier work, a licensed plumber and your local code have the final word.
