Toilet Rough-In 10, 12 or 14 Inch: How to Measure It, Which TOTO, American Standard and Kohler Models Ship at Each Size, and the Seal That Fits
Rough-in is finished wall to the centre of the closet bolts (TOTO), near 10, 12 or 14 in; 12 in is standard. Model numbers by rough-in from maker spec sheets.
- Verified
- Updated
- 7 min read
- 17 sources
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Short answer
Toilet rough-in is the distance from the back of the finished wall to the centre of the drain flange, or, with the toilet still installed, to the centre of one of its mounting bolts, as TOTO’s measuring tip defines it. TOTO says the result should be close to 10, 12 or 14 inches, and if it is not, measure again; 12 inches is the standard, with 10 and 14 inches found in older homes and small bathrooms. The same bowl ships in two rough-ins under two model numbers: TOTO’s Drake 1.28 GPF is CST776CEFG at 12 inches (spec sheet SS-02049) and CST776CEFG.10 at 10 inches (SS-02051), and American Standard’s 10 inch Cadet PRO is model 609AB001.020. Kohler’s Highline sheets K-3658-RA and K-3493 print a standard 12 inch rough-in only. Measure from the wall, not the baseboard, then buy the model whose spec sheet prints your number: a 12 inch toilet leaves a gap in a 14 inch room and does not fit a 10 inch one.
The picks
Tape reads 12 in, the standard
TOTO Drake two-piece elongated 1.6 GPF, 12 in rough-in (CST776CSFG#01)
TOTO spec sheet SS-02004: 12 in rough-in, 1.6 GPF, two-piece elongated, ASME A112.19.2/CSA B45.1, IAPMO (cUPC); seat sold separately
Tape reads 10 in, and you want the seat in the box
TOTO Drake two-piece elongated 1.28 GPF, 10 in rough-in, SoftClose seat (MS776124CEFG.10#01)
TOTO spec sheet SS-02021: 10 in rough-in, 1.28 GPF, SS124 SoftClose seat included, ASME A112.19.2/CSA B45.1, IAPMO (cUPC), EPA WaterSense
Flange sits at floor level and you want the conventional seal
Fluidmaster 7511 wax ring with flange and bolts
Fluidmaster seal family page: 7511 is the flanged wax seal with bolts; a wax ring is single-use, so scrape off the old one first (7530 sheet)
Flange is above the floor or up to 1/4 in below it, or you may need to reseat the bowl
Fluidmaster 7530 Better Than Wax wax-free seal
Fluidmaster 7530 instruction sheet: rubber seal, slide-on spacer, two brass bolts, nuts and washers; spacer removed when the flange is above the floor; limited 10 year warranty
If the tape reads 11 or 13 inches, or the drain sits off to one side, skip the toilet table: the fix is an offset flange, not a different toilet.
How do you measure a toilet rough-in?
The closet bolts are the two bolts under the plastic caps at the base of the bowl; the flange is the floor ring they fasten to.
| Situation | Measure from | Measure to | Who says so |
|---|---|---|---|
| Toilet removed | Back of the finished wall | Centre (not the edge) of the drain pipe or flange | TOTO tips page |
| Toilet still installed | Back of the finished wall | Centre of one of the mounting bolts | TOTO tips page |
| American Standard’s wording | Finished wall | Centre of the mounting holes on the floor flange | American Standard Champion 4 page |
| Result check | The number should be close to 10, 12 or 14 in; if not, measure again | TOTO tips page |
The baseboard is not the wall: a tape hooked on it reads short by its thickness. If a skirt hides the bolts, measure to the flange centre after removal.
Which models ship at 10, 12 and 14 inch rough-in?
Each row is what the maker’s own sheet prints. TOTO’s 10 inch Drake is the same bowl with a .10 suffix.
| Maker and model | Rough-in | Flush | Seat | Document |
|---|---|---|---|---|
| TOTO Drake CST776CEFG (#01 Cotton, #03 Bone, #11, #12) | 12 in | 1.28 GPF | Sold separately | SS-02049 |
| TOTO Drake CST776CEFG.10 | 10 in | 1.28 GPF | Sold separately | SS-02051 |
| TOTO Drake MS776124CEFG | 12 in | 1.28 GPF | SS124 SoftClose included | SS-02006 |
| TOTO Drake MS776124CEFG.10 | 10 in | 1.28 GPF | SS124 SoftClose included | SS-02021 |
| TOTO Drake CST776CSFG | 12 in | 1.6 GPF | Sold separately | SS-02004 |
| TOTO Drake CST776CSFG.10 | 10 in | 1.6 GPF | Sold separately | SS-02019 |
| American Standard Cadet PRO 609AB001.020 | 10 in | 1.28 gpf | Seat and wax ring included | Product page |
| American Standard Champion 4 731BA001S (Lowe’s exclusive) | 12 in (305 mm) minimum | 1.6 gpf | Included | Spec sheet |
| Kohler Highline Classic K-3658-RA | Standard 12 in (305 mm) | 1.28 gpf | Not listed | Spec sheet |
| Kohler Highline Classic K-3493 | Standard 12 in (305 mm) | 1.6 gpf | Not listed | Spec sheet |
Every TOTO, Kohler and American Standard sheet above prints ASME A112.19.2/CSA B45.1; the TOTO sheets add IAPMO (cUPC), and the 1.28 GPF TOTO, Cadet PRO and K-3658-RA pages add EPA WaterSense.
No 14 inch spec sheet from any of the three makers was opened this session, so the table has no 14 inch row. TOTO’s tips page says a 12 inch toilet fits a 14 inch rough-in with a sizable gap behind the tank, and that its Unifit adapter sets select skirted TOTO toilets (the Carlyle II is named) to 10, 12 or 14 inches. None of the Drake spec sheets opened mentions Unifit, so do not assume it fits a Drake. The American Standard Cadet Pro listing names a 10 inch rough-in in its title; it could not be matched to model 609AB001.020 this session, so check the model number on the box. The best toilet comparison ranks these bowls on flush performance once the rough-in is settled.
What if the tape reads 11 or 13 inches, or the drain is off-centre?
An offset flange is a closet flange whose pipe socket is set to one side of its ring. Oatey says it repositions the toilet connection up to 2 inches in any direction, needs an oval cut in the floor, and is compatible with most standard wax rings and seals.
| Oatey flange | Offset | Fixes |
|---|---|---|
| PVC Level Fit, stainless steel ring | 2 in | A 10 or 14 in drain under a 12 in toilet, per Oatey’s article |
| ABS Level Fit, stainless steel ring (43500 is the ABS listing) | 1-1/2 in | An 11 or 13 in reading, or a sideways miss |
Oatey’s article is the only maker page opened that describes the offset as a rough-in correction, so the 2 inch figure is Oatey’s. Whether the listed 43500 is the exact SKU on Oatey’s ABS page was not confirmed.
Wax ring or wax-free seal, and which closet bolts?
A wax ring is the single-use beeswax seal between bowl and flange; a wax-free seal is a rubber seal that can be lifted and reseated. Fluidmaster’s 7530 instruction sheet sets the fit by flange height.
| Part | Type | Flange position rule | Source |
|---|---|---|---|
| Fluidmaster 7511 | Flanged wax seal with bolts | Scrape off all old wax before any new seal | Fluidmaster seal page; 7530 sheet |
| Fluidmaster 7510, 7512, 7513, 7514, 7516 | Wax seals, 7513 thick flanged | As above | Fluidmaster seal page |
| Fluidmaster 7530 | Wax-free rubber seal with spacer and two brass bolts | Flange above floor: remove the spacer. Even with floor to 1/4 in below: spacer plus seal. More than 1/4 in below: spacer plus a second seal, bought separately | 7530 instruction sheet |
| Kohler 1023457 | Wax ring and hardware kit | Listed as the accessory for the K-3658-RA | Kohler K-3658-RA sheet |
| Danco 88773A | Closet bolts, 5/16 x 2-1/4 in, break-away | Listing title only; Danco’s page was not opened | Listing |
Fluidmaster’s sheet also says not to overtighten the nuts, since the bowl or the flange may crack, and prints a limited 10 year warranty on the 7530. The Cadet PRO ships with a wax ring and the 7530 kit with its own bolts, so a separate bolt kit is for a reinstall with corroded or short bolts.
Measure, then buy the number on the sheet
The TOTO Drake CST776CSFG is the 12 inch pick and the MS776124CEFG.10 the 10 inch pick, because TOTO prints the rough-in on each sheet. The flaw: the 12 inch Drake linked here is the 1.6 GPF bowl without a seat, and no 12 inch 1.28 GPF Drake listing was confirmed in stock this session. Seat sizing is its own measurement, on the round vs elongated seat page. Skip both if your tape reads 14 inches: no maker sheet opened prints a 14 inch model, and a 12 inch bowl will leave the gap TOTO describes.
Frequently asked questions
Do you measure toilet rough-in from the baseboard or the wall?
From the finished wall, never the baseboard. TOTO's measuring tip says to measure from the back of the finished wall to the centre of the drain flange, or to the centre of one mounting bolt if the toilet is still in place. American Standard words it as finished wall to the centre of the mounting holes on the floor flange. A baseboard gives a short reading.
Can a 12 inch rough-in toilet go on a 10 inch rough-in?
No. TOTO ships the Drake as a separate .10 model (CST776CEFG.10, spec sheet SS-02051) for 10 inch rooms, and its tips page says to buy the exact rough-in of the old toilet. Oatey says an offset flange can move the connection up to 2 inches, but that is a floor and drain job, not a swap; the simpler fix is a 10 inch toilet.
Can a 12 inch rough-in toilet go on a 14 inch rough-in?
TOTO says yes, with a cost: replacing a 14 inch rough-in toilet with a 12 inch one is possible but leaves a sizable gap between the tank and the finished wall. No 14 inch spec sheet from TOTO, American Standard or Kohler was opened this session, so this page prints no 14 inch model number. TOTO's Unifit adapter covers 10, 12 or 14 inches, on select skirted TOTO toilets only.
Wax ring or wax-free seal?
Both seal the same joint. Fluidmaster's 7530 instruction sheet sets the wax-free rule by flange height: remove the spacer if the flange sits above the floor, use spacer plus seal when it is even with the floor to 1/4 inch below, and add a second seal below that. Fluidmaster lists wax seals 7510 to 7516 alongside it; Kohler's K-3658-RA sheet names its own wax ring and hardware kit, 1023457.
What does an offset toilet flange do?
Oatey says an offset flange repositions the toilet connection up to 2 inches in any direction, needs an oval cut in the floor, and works with most standard wax rings and seals. Oatey's PVC Level Fit offset flange prints a 2 inch offset and the ABS version 1-1/2 inch. It fixes an 11 or 13 inch reading or a sideways drain.
Fact sheet and how to cite this page
- Answer
- TOTO defines rough-in as the distance from the back of the finished wall to the centre of the drain flange, or to the centre of a mounting bolt if the toilet is still installed, and says it should be close to 10, 12 or 14 inches, with 12 inches the standard. TOTO’s Drake 1.28 GPF is CST776CEFG at 12 inches and CST776CEFG.10 at 10 inches; American Standard’s 10 inch Cadet PRO is 609AB001.020.
- Applies to
- TOTO Drake CST776CEFG, 1.28 GPF, 12 in rough-in (spec sheet SS-02049)
- TOTO Drake CST776CEFG.10, 1.28 GPF, 10 in rough-in (spec sheet SS-02051)
- TOTO Drake MS776124CEFG and MS776124CEFG.10, 1.28 GPF with SS124 SoftClose seat, 12 and 10 in (SS-02006, SS-02021)
- TOTO Drake CST776CSFG and CST776CSFG.10, 1.6 GPF, 12 and 10 in (SS-02004, SS-02019)
- American Standard Cadet PRO 609AB001.020, 1.28 gpf, 10 in rough-in (product page)
- American Standard Champion 4 731BA001S, 1.6 gpf, 12 in minimum rough-in (spec sheet)
- Kohler Highline Classic K-3658-RA and K-3493, standard 12 in rough-in (spec sheets)
- Compatibility basis
- TOTO’s rough-in tips page for the definition and measuring method; TOTO spec sheets SS-02049, SS-02051, SS-02006, SS-02021, SS-02004 and SS-02019; American Standard’s Champion 4 spec sheet and Cadet PRO product page; Kohler spec sheets K-3658-RA and K-3493; Oatey’s offset flange article and product pages; Fluidmaster’s 7530 instruction sheet and seal family page
- Assumptions
- No maker spec sheet for a 14 inch rough-in toilet was opened this session; the 14 inch figure rests on TOTO’s tips page alone, so the model table carries 10 and 12 inch rows only.
- The Champion 4 sheet opened (731BA001S) is a 12 inch, Lowe’s-exclusive model; no 10 inch Champion 4 or 10 inch Kohler Highline sheet was found, so neither is claimed.
- The American Standard Cadet PRO Amazon listing names a 10 inch rough-in in its title but could not be matched to the 609AB001.020 model number on the maker page, so it is linked as the listing describes it and not as that model.
- Danco’s closet bolt page was not opened this session; the closet bolt size comes from the listing title only and the page cites no Danco specification.
- The ASME A112.19.2/CSA B45.1 standard is named because TOTO, Kohler and American Standard print it on their sheets; the standard’s own text was not opened.
- Method
- Definitions, measuring steps, rough-in dimensions, model numbers, flange offsets and seal fitting rules copied from each maker’s own tips page, spec sheet, product page or instruction sheet. OwnerSpec measured no bathroom and installed no toilet; this is a spec lookup.
- Primary source
- TOTO USA, Toilet Rough-ins and the Cleverness of TOTO's Unifit Rough-in: definition, how to measure, 12 in standard, 10 and 14 in alternatives (manufacturer or vendor document)
- Facts verified
- Last updated
- Cite as
- OwnerSpec, "Toilet Rough-In 10, 12 or 14 Inch: How to Measure It, Which TOTO, American Standard and Kohler Models Ship at Each Size, and the Seal That Fits", https://ownerspec.com/plumbing/parts/toilet-rough-in-10-12-14-inch/, facts verified 3 October 2026.
Every figure above also appears, with its source, in the article. All sources ยท How OwnerSpec verifies numbers
Sources
- TOTO USA, Toilet Rough-ins and the Cleverness of TOTO's Unifit Rough-in: definition, how to measure, 12 in standard, 10 and 14 in alternatives (manufacturer or vendor document)
- TOTO spec sheet SS-02049, Drake CST776CEF(R)(G): 12 in rough-in, 1.28 GPF, 2-1/8 in trap, ASME A112.19.2/CSA B45.1, IAPMO (cUPC), EPA WaterSense (manufacturer or vendor document)
- TOTO spec sheet SS-02051, Drake CST776CEF(R)G.10: 10 in rough-in, 1.28 GPF, ASME A112.19.2/CSA B45.1, IAPMO (cUPC), EPA WaterSense (manufacturer or vendor document)
- TOTO spec sheet SS-02006, Drake MS776124CEFG: 12 in rough-in, 1.28 GPF, SS124 SoftClose seat included (manufacturer or vendor document)
- TOTO spec sheet SS-02021, Drake MS776124CEFG.10: 10 in rough-in, 1.28 GPF, SS124 SoftClose seat included (manufacturer or vendor document)
- TOTO spec sheet SS-02004, Drake CST776CSF(G): 12 in rough-in, 1.6 GPF, ASME A112.19.2/CSA B45.1, IAPMO (cUPC) (manufacturer or vendor document)
- TOTO spec sheet SS-02019, Drake CST776CSFG.10: 10 in rough-in, 1.6 GPF, 2-1/8 in trap, mount the flange at a nominal 10 in to keep the tank-to-wall gap (manufacturer or vendor document)
- American Standard spec sheet 731BA001S, Champion 4 chair height round front: designed to rough-in at a minimum of 305 mm (12 in) from finished wall to centreline of outlet, 1.6 gpf, ASME A112.19.2/CSA B45.1 (manufacturer or vendor document)
- American Standard, Champion 4 two-piece 1.6 gpf round front toilet 731BA001S.020: '12-inch rough-in: measurement from the finished wall to the center of mounting holes on the floor flange' (manufacturer or vendor document)
- American Standard, Cadet PRO two-piece 1.28 gpf chair height elongated 10-inch rough toilet 609AB001.020: 10 in rough-in in the product name, WaterSense, seat and wax ring included (manufacturer or vendor document)
- Kohler spec sheet K-3658-RA, Highline Classic Comfort Height 1.28 gpf: standard 12 in (305 mm) rough-in, three-bolt installation, ASME A112.19.2/CSA B45.1, WaterSense, accessory 1023457 wax ring/hardware kit (manufacturer or vendor document)
- Kohler spec sheet K-3493, Highline Classic 1.6 gpf: standard 12 in (305 mm) rough-in, 2-1/4 in trapway, ASME A112.19.2/CSA B45.1 (manufacturer or vendor document)
- Oatey, When Should You Use an Offset Toilet Flange: repositions the connection up to 2 in in any direction, oval floor cut, compatible with most wax rings and seals, standard rough-in 12 in (manufacturer or vendor document)
- Oatey PVC Level Fit Offset Closet Flange with Stainless Steel Ring: 2 in offset (manufacturer or vendor document)
- Oatey ABS Level Fit Offset Closet Flange with Stainless Steel Ring: 1-1/2 in offset (manufacturer or vendor document)
- Fluidmaster 7530 Better Than Wax installation instructions (part 7-1338): kit contents, flange-height rules, do not overtighten, limited 10 year warranty (manufacturer or vendor document)
- Fluidmaster, 7530 Better Than Wax wax-free toilet seal: lists wax seals 7510, 7511, 7512, 7513, 7514, 7516 alongside the wax-free 7530 (manufacturer or vendor document)