Elongated vs Round Toilet: Size, Clearance, Which to Buy

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Quick answer from a licensed plumber: Round vs elongated is a bowl-length choice, about 2 inches. On the maker drawings I opened, the distance from the seat-bolt holes to the front of the bowl is 16-1/2 inches for TOTO’s round Drake and 18-1/2 inches for its elongated Drake. American Standard’s Cadet 3 drawings show 16-3/8 and 18-1/4 inches. On the TOTO pair, the whole toilet is 26-3/8 inches deep round and 28 inches deep elongated, measured from the wall. Rough-in, seat-bolt spacing and seat height do not depend on the shape.

Before you choose, measure the clear floor in front of the bowl. The 2021 IPC calls for at least 21 inches there. The UPC calls for 24 inches; Washington amends that to 21 inches in dwelling units. If the extra 2 inches would break that, look at a round bowl or a compact elongated one.

People agonize over this in the showroom and get it wrong at home, because the showroom has no walls. Below: the maker numbers, how to measure the right way, what the codes say, and how to match the seat.

Round vs elongated toilet at a glance

	Round	Elongated
Seat-bolt holes to front of bowl	TOTO Drake CST743S: 16-1/2 in. American Standard Cadet 3 (270D): 16-3/8 in.	TOTO Drake CST744S: 18-1/2 in. American Standard Cadet 3 (270A): 18-1/4 in.
Overall depth from the wall (TOTO Drake pair, both 12 in. rough-in)	26-3/8 in.	28 in. That is 1-5/8 in. more (our arithmetic).
Seat-bolt hole spacing	5-1/2 in. on the TOTO, American Standard and Kohler sheets I opened
Bowl width and water surface (TOTO Drake pair)	14 in. wide. Water surface 10-1/4 x 8-1/2 in.	14 in. wide. Water surface 10-1/4 x 8-1/2 in.
Seat height (TOTO Drake pair, TOTO’s drawing label)	15-5/8 in.	15-5/8 in.
Tank (TOTO Drake pair)	ST743S with the C743E round bowl	The same ST743S with the C744E elongated bowl
Rough-in	Set by the model, not the shape. American Standard says most of its toilets fit a 12 in. rough-in and it offers 10 in. and 14 in. models.
Seat length	Round-front seat: 16-3/4 in. or less (Kohler Asia Pacific)	Elongated seat: 18-5/8 in. or more (Kohler Asia Pacific)
What the makers say	Kohler describes its round-front bowls as a fit for smaller baths and powder rooms.	Kohler says its elongated bowls add room and comfort. Its Cimarron and Highline sheets add that plumbing codes may require elongated toilets and open-front seats in public bathrooms.

Every number above comes from a maker spec sheet, drawing or knowledge-base page listed under Sources. Overall depth depends on rough-in as well as bowl shape: American Standard’s Cadet 3 round sheet shows 26-1/4 in. at a 10 in. rough-in and its elongated sheet shows 30-1/4 in. at 12 in., so that pair cannot be compared on overall depth. Compare the seat-hole-to-front figure instead.

How to measure: seat bolts, not floor bolts

Find the two holes at the back of the bowl rim where the seat hinges bolt on. They are 5-1/2 inches apart. Measure from the center of those two seat bolts straight forward to the front edge of the bowl. That is the dimension TOTO’s and American Standard’s drawings label. Near 16-1/2 inches is round. Near 18-1/2 inches is elongated. Compact elongated bowls do not always follow that rule (see below), so if the toilet is sold as compact elongated, go by the model number on the maker sheet. Kohler’s Asia Pacific guide uses the same idea for a seat: measure from the hinge bolt to the front of the seat.

The closet bolts that hold the toilet to the floor are a different measurement. They set the rough-in, which American Standard describes as the distance from the center of those bolts to the finished wall. Do not use them for bowl length.

If you are replacing a seat rather than a toilet, that one measurement is the whole job. Our toilet seat size guide and toilet seat guide go through the rest of the fit.

Where the two inches actually matter

This is the part the showroom cannot tell you, and it is where people get it wrong.

Clearance in front of the bowl

Two plumbing codes give different numbers. The 2021 International Plumbing Code (IPC) 405.3.1 says there shall be not less than a 21-inch clearance in front of a water closet to any wall, fixture or door. The Uniform Plumbing Code (UPC) 402.5 says the clear space in front of a water closet, lavatory or bidet shall be not less than 24 inches. States can amend it: Washington’s adoption allows 21 inches in dwelling units and sleeping units. Check the edition and amendments your city adopted.

What that means with a tape measure (our arithmetic): if a round bowl leaves 22 inches clear, the 1-5/8 inches of extra depth on the elongated TOTO Drake leaves 20-3/8, which is under the IPC’s 21. In a powder room where the toilet faces a wall or a vanity, that can be the difference between an install that passes and one that does not. Measure the finished clear space, not the space you have during demolition.

Side clearance

Both codes set the same side distance: a water closet shall not be set closer than 15 inches from its center to a side wall or obstruction. Bowl shape does not change this one, but a room that is tight on side clearance is often tight in front too. Check both while you have the tape out.

Accessible bathrooms (ADA)

The 2010 ADA Standards, section 604, put the water closet centerline 16 to 18 inches from the side wall (604.2), require clearance around the water closet of at least 60 inches measured from the side wall and at least 56 inches from the rear wall (604.3.1), and set the seat height at 17 to 19 inches, or 15 to 19 inches in residential dwelling units (604.4). None of those three sections names a bowl shape, so the ADA does not pick round or elongated for you. It does make front and side space a bigger question than bowl length.

The door

The most common real-world failure is an inward-swinging bathroom door that clears a round bowl and catches an elongated one. Before buying, mark the extra 2 inches on the floor with tape and swing the door. It takes thirty seconds and it has saved more than one return trip.

Walking past it

In a narrow bathroom where you pass between the toilet and a tub or vanity, 2 inches off the walkway is noticeable every day. That is the argument for round that nobody makes in a showroom.

Where each shape fits

If the space is there, elongated is the roomier bowl. Kohler’s spec sheets say the elongated bowl offers added room and comfort. That is the maker’s claim; I have not tested it. Two more practical points:

Public and commercial bathrooms. The 2021 IPC (425.2 and 425.3) requires elongated bowls and hinged open-front seats in public and employee toilet facilities, and Kohler’s Cimarron (K-31621) and Highline (K-3493) sheets carry a similar warning. If you are fitting out anything other than a home, check the code your area adopted and ask the inspector.
Bidet seats. They are sold in round and elongated versions and have to match the bowl. Kohler’s Wellworth elongated sheet (K-3948) lists an elongated bidet seat (K-4108) as an accessory. Our bidet install guide covers the rest.

Round is the shape Kohler points to for smaller baths and powder rooms, and it is the one that keeps the most floor. Choose it when the tape measure says the extra 2 inches will not fit, not because it looks smaller in the showroom.

Compact elongated: shorter overall, bowl length varies

Some makers sell an elongated toilet that is shorter overall, called compact elongated. Gerber’s spec sheets are the clearest pair I found. The Viper Force compact elongated (GRS48350) lists a depth of 27-3/4 inches. The standard Viper Force elongated (GRS48352) lists 29-1/2 inches. That is 1-3/4 inches less (our arithmetic). Both drawings show the same 18-9/16 inches from the seat holes to the front of the bowl, so on Gerber’s pair the saving is not a shorter bowl. Gerber’s sheets do not say where the depth comes from, and the two toilets use different bowl and tank part numbers.

American Standard goes further: its Compact Cadet 3 one-piece spec sheet says the elongated bowl fits in the same space as a round-front toilet, with a nominal 28-1/2 inch length. That is the maker’s claim, and its drawing shows only 16-5/8 inches from the seat-post holes to the front of the bowl, close to the round figures above. So a compact elongated bowl may or may not be shorter at the seat; the maker sheet for your model number is the way to know. Put the sheet depth of the toilet you are replacing next to the sheet depth of the compact model before you order.

Our compact toilet picks list each model’s overall depth.

What bowl shape does NOT change

These get bundled into the decision and should not be:

Rough-in. American Standard describes it as the distance from the center of the toilet bolt holes to the finished wall, and says most of its toilets fit a 12-inch rough-in. Bowl shape has nothing to do with it. Get the measurement before you buy anything, and see toilet rough-in size.
Height. Standard and chair height are set by the model. American Standard lists 15 inches for standard height and 16-1/2 inches for right height. TOTO’s round and elongated Drake both list a 15-5/8 inch seat height. A separate decision, covered in comfort height vs standard toilet.
Flush system. TOTO lists the same G-Max flush system, the same 1.6 gpf and the same 10-1/4 x 8-1/2 inch water surface on the round and the elongated Drake. Our best toilets guide covers what clears.
Tank parts. TOTO pairs the same ST743S tank with both Drake bowls. Fill valve, flapper and supply parts follow the tank, so see fill valve replacement.

Toilets and seats to check

These are models I read the maker documents for, one per bowl type. I linked them because Amazon listed them as in stock and sold by Amazon on September 29, 2026. The Kohler and TOTO sheets say the seat is sold separately.

Model	Bowl	From the maker sheet	Amazon
Kohler Wellworth (K-3997)	Round-front, 1.28 gpf	12 in. rough-in. Overall depth 27-3/4 in. on the sheet dated 4-8-2020. Seat-mounting holes 5-1/2 in. Seat and supply line sold separately.	Check the Wellworth K-3997 on Amazon
TOTO Drake (CST776CSFG)	Elongated, Universal Height, 1.6 gpf	12 in. rough-in. Overall depth 28-3/8 in. Seat holes to front of bowl 18-1/2 in. Seat not included.	Check the Drake CST776CSFG on Amazon
Gerber Viper Force (GRS48350)	Compact elongated, ErgoHeight, 1.28 gpf	12 in. rough-in. Depth 27-3/4 in. against 29-1/2 in. for Gerber’s standard elongated Viper Force. Gerber’s page says the soft-close seat is included.	Check the Viper Force GRS48350 on Amazon
Kohler Stonewood seat (K-20467-0)	Round	The Amazon listing says it fits most round-front toilets.	Check the round Stonewood seat on Amazon
Kohler Stonewood seat (K-20466-0)	Elongated	The Amazon listing says it fits most elongated and compact-elongated toilets.	Check the elongated Stonewood seat on Amazon

Dimensions on maker sheets are nominal, and Amazon listings sometimes print different numbers than the maker sheet does. Check the sheet for your exact model number before you cut into a floor plan.

So which should you buy?

Full bathroom with room to spare: elongated. It is the roomier bowl by the makers’ own description.

Powder room, or a door that swings in: measure the clear floor first. If you are within 2 inches of the IPC’s 21 inches (or the UPC’s 24), go round or compact elongated.

Narrow bathroom you squeeze past: round. You will notice the walkway every day.

Commercial or public bathroom: elongated, with a hinged open-front seat (2021 IPC 425.2 and 425.3), and confirm with the inspector.

Buying a seat, not a toilet: measure from the seat bolts to the front of the bowl and match the shape.

Bowl shape settled? The remaining choice is construction. One-piece vs two-piece covers cleaning, parts and the weight problem that decides it for most upstairs bathrooms. Replacing it yourself: how to replace a toilet.

Frequently asked questions

What is the difference between a round and elongated toilet?

Bowl length. On TOTO’s drawings for the round Drake (CST743S) and the elongated Drake (CST744S), the distance from the seat-bolt holes to the front of the bowl is 16-1/2 inches for round and 18-1/2 inches for elongated. American Standard’s Cadet 3 drawings show 16-3/8 and 18-1/4 inches. On the TOTO pair, overall depth from the wall is 26-3/8 inches round and 28 inches elongated. Rough-in, seat-bolt spacing and seat height do not depend on the shape.

How do I know if my toilet is round or elongated?

Measure from the center of the two seat-bolt holes at the back of the bowl rim, straight forward to the front edge of the bowl. Near 16-1/2 inches is round; near 18-1/2 inches is elongated. A compact elongated bowl can measure shorter, so check the model number if the toilet is sold as compact elongated. Do not measure from the closet bolts at the floor. Those set the rough-in, not the bowl length.

Does bowl shape change the rough-in?

No. Rough-in is the distance from the finished wall to the center of the closet bolts. American Standard says most of its toilets fit a 12-inch rough-in and sells 10-inch and 14-inch models. The bowl shape is chosen separately, so confirm the rough-in before you buy either one.

Can I put an elongated toilet in a small bathroom?

Sometimes. Measure the clear floor in front of the bowl first. The 2021 IPC calls for at least 21 inches in front of a water closet, and the UPC calls for 24 inches (Washington amends that to 21 inches in dwelling units). An elongated bowl uses about 2 inches more floor than a round one, so a room that is close to the limit can tip over it. A compact elongated or a round toilet keeps that space.

What is a compact elongated toilet?

A toilet with an elongated bowl and a shorter overall depth. Gerber lists its Viper Force compact elongated (GRS48350) at 27-3/4 inches deep and its standard Viper Force elongated (GRS48352) at 29-1/2 inches. Both drawings show 18-9/16 inches from the seat holes to the front of the bowl, so on that pair the saving is not in the bowl length. American Standard says its Compact Cadet 3 elongated bowl fits in the same space as a round-front toilet, and its drawing shows 16-5/8 inches from the seat-post holes to the front. Compare the depth on each maker’s sheet.

Are round and elongated toilet seats interchangeable?

No. The seat has to match the bowl. Kohler’s Asia Pacific guide says to measure the current seat from the hinge bolt to the front of the seat: a round-front seat measures 16-3/4 inches or less and an elongated seat 18-5/8 inches or more. A seat that is too short leaves the rim exposed, and one that is too long overhangs the front.

Do round and elongated bowls use the same tank?

It depends on the model, but it can be the same. TOTO’s spec sheets for the round CST743S and the elongated CST744S both list the ST743S tank and cover with their different bowls. That is why tank parts such as the fill valve and flapper do not depend on the bowl shape. Check the tank number on your own toilet.

Do building codes require an elongated toilet?

For public and employee bathrooms, the 2021 IPC does: section 425.2 says water closet bowls for public or employee toilet facilities shall be of the elongated type, and 425.3 requires hinged open-front seats there. Kohler’s Cimarron and Highline spec sheets carry a similar warning. The rule names public and employee facilities, not a bathroom in a private home. Check the code your area adopted if your job falls under it.

Why Trust Plumbing Picks

Plumbing Picks is written by a licensed Georgia journeyman plumber. Every number on this page comes from the maker spec sheets, drawings, knowledge-base pages and code texts listed below, which I opened and read on September 29, 2026; nothing here is from hands-on testing. Each linked product was shown as in stock and sold by Amazon when I checked on September 29, 2026. Where a link goes to Amazon we may earn a commission at no extra cost to you. Nobody pays to be included. More on who writes this and how we pick.

Elongated vs Round Toilet: Size Difference and Which to Buy