One-piece chair-height toilets with bidet compatibility and compact footprint

The best fit is usually a compact elongated, one-piece toilet with chair-height seating and a standard 12-inch rough-in. You can get a more comfortable seat height without taking up the extra floor space of a conventional elongated toilet.

My first choice is the KOHLER Santa Rosa K-30812. It is just 27¾ inches long, has a 16½-inch rim height, and is explicitly designed to provide chair-height seating.www.studiokohler.com+1

Best models to shortlist

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1. KOHLER Santa Rosa K-30812

(Best overall)

27¾″ long · 17⅝″ wide · 16½″ rim height

• Compact elongated bowl with chair-height design.
• One-piece construction is easy to clean.
• Bidet compatibility: KOHLER lists Santa Rosa as compatible with several of its bidet seats, but not all. Verify the exact seat before buying.www.studiokohler.com+4

Manufacturer specifications and details

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2. KOHLER San Souci K-5172

Compact elongated · Comfort Height · 1.28 GPF

• Another strong choice for a small bathroom, with a concealed trapway for a streamlined appearance.
• Bidet compatibility: KOHLER's compatibility chart confirms fit with selected seats, including the Purewash K-98804 and C3-050. Other models are not compatible, so match the seat carefully.www.studiokohler.com+4

Manufacturer specifications and details

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3. KOHLER Santa Rosa K-3811

27¾″ long · 18¾″ wide · 16½″ rim height

• An alternative Santa Rosa configuration with a compact elongated bowl and chair-height seating.
• Worth considering if you prefer its particular flush system or find it available locally.
• Bidet compatibility: Check the exact bidet seat model against the toilet's specifications before purchase.dev.studiokohler.com+2

Manufacturer specifications and details

What to check before you buy

• Seat height: The rim height is not the final sitting height. The toilet seat adds roughly another inch or so, depending on the seat.
• Bidet-seat fit: Check bowl length, mounting-hole spacing, hinge clearance, and whether the seat can sit flush against the bowl. Electric seats also need a nearby GFCI outlet.
• Actual footprint: Measure from the finished wall to the front of your existing toilet, and confirm the rough-in distance (usually 12 inches).
• Avoid compatibility assumptions: A toilet described as “bidet compatible” may only work with certain seats. The manufacturer compatibility chart is more useful than the elongated-bowl label alone.

My recommendation: Start with the Santa Rosa K-30812 for its especially short 27¾-inch length, then choose a bidet seat whose compatibility is explicitly confirmed.

Would you like me to compare the best compatible bidet seats for these two models, or find more compact one-piece toilets under 28 inches long?

Finding a one-piece toilet that hits all three requirements—chair-height (Universal/Comfort Height), bidet-seat friendly , and compact/short footprint —can be tricky because one-piece units often feature bulky integrated tank moldings.

Standard elongated toilets usually run 29 to 30 inches in depth, but "compact" models safely shave that down to roughly 26.5 to 28 inches. The standout models that balance these constraints without an oversized footprint include:

1. TOTO Aquia IV 1-Piece (WASHLET+ Ready)

• Footprint / Depth: ~27.375 inches (Very compact for a skirted, modern design)
• Seating Height: Universal Height (Chair-height / ADA compliant, approx. 17.25 inches to bowl rim)
• Bidet Compatibility: Exceptional. Available in a WASHLET+ version which features a concealed internal channel to route the bidet power cord and water supply cleanly through the porcelain, avoiding external hose clutter entirely. It natively fits TOTO electronic bidet seats seamlessly.totousa.com+2

2. KOHLER San Souci Comfort Height

• Footprint / Depth: 28 inches (Compact elongated bowl profile with a low-profile, flowing tank)
• Seating Height: Comfort Height (Chair-height, 16.5 inches to rim)
• Bidet Compatibility: Moderate/Conditional. While it accepts many standard elongated bidet seats (like the Alpha JX or Kohler’s specific Purewash lines), its curved "French-style" integrated tank leaves tighter clearance at the mounting bolts. Bulky smart-bidet seats with very deep rear housings may overhang slightly or require careful model matching.kohler.com+2

3. TOTO Carlyle II 1-Piece (WASHLET+ Ready)

• Footprint / Depth: 28.25 inches (Sleek, streamlined traditional-to-modern profile)
• Seating Height: Universal Height (Chair-height, approx. 16.13" to 17.25" depending on the specific sub-variant and seat combo)
• Bidet Compatibility: Exceptional. Like the Aquia, the Carlyle II has designated WASHLET+ configurations that accommodate TOTO’s high-end electronic bidet seats with zero visible hoses or cords.dimensions.com+1

Key Recommendation Summary

If seamless electronic bidet integration and a tighter, cleaner look are your highest priorities, go with a TOTO Universal Height 1-Piece with WASHLET+ capability (such as the Aquia IV 1-Piece) . Skirted TOTO models offer straight-walled back profiles that prevent compatibility headaches common with uniquely curved one-piece tanks.lowes.com+1

If you have a specific rough-in size (like 10 inches or 12 inches) or a preferred bidet brand already in mind, let me know and I can verify the exact fit for you.totousa.com

For a compact bathroom, I’d focus on one-piece toilets with an elongated, chair-height bowl and a standard bidet-seat mounting arrangement. The best choice depends on whether you want to add your own bidet seat or prefer a toilet that already includes bidet functions.

My first choice to investigate is the KOHLER San Souci K-5172 because it combines a compact elongated bowl with Kohler’s Comfort Height seating. It is specifically designed to occupy about the same footprint as a traditional round-front toilet.www.kohler.com+1

My top recommendations

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1. KOHLER San Souci K-5172

(Best for small bathrooms)

• One-piece, compact elongated design
• Comfort Height seating
• 1.28 gallons per flush
• Standard 12-inch rough-in

Best if you want a reputable brand and a compact footprint. Check the exact bidet seat's tank clearance before buying.www.kohler.com+1

View at KOHLER

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2. American Standard Compact Cadet 3

Best practical alternative

• Compact, elongated, one-piece design
• 18.5-inch height measured with the included seat
• WaterSense-certified, 1.28 GPF flush
• Slow-close seat included

A strong choice for a small room where adult seating height matters. Because the included seat must be removed for a replacement bidet seat, verify the mounting dimensions and hinge clearance first.www.americanstandard-us.com

View at American Standard

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3. KOHLER Portrait K-3826

Best traditional styling

• One-piece compact elongated bowl
• Comfort Height seating
• Concealed trapway for easier cleaning
• Standard 12-inch rough-in

Another option worth considering if you prefer a more traditional appearance. KOHLER lists its PureWash E750 bidet seat as a recommended accessory for this model.resources.kohler.com

View manufacturer specifications

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4. TOTO UltraMax

Best premium alternative

• One-piece, elongated design
• Universal-height seating on compatible models
• Available in configurations paired with TOTO WASHLET seats

Worth investigating if you want a coordinated toilet-and-bidet setup. Confirm the exact model and its dimensions, since not every UltraMax configuration has the same features.www.lowes.com

View TOTO's website

What to check before purchasing

A toilet being labeled “bidet compatible” doesn't guarantee that every bidet seat will fit. Check these four things:

• Seat height: Aim for roughly 17–19 inches from the floor to the top of the seat, including the seat itself.
• Bowl shape: Match the bidet seat to the toilet's elongated or round shape.
• Mounting clearance: Measure from the seat-bolt holes to the tank. Some bidet seats need at least 1½ inches of clearance behind the mounting holes.help.brondell.com
• Room depth: Check the complete front-to-back projection, not just the bowl dimensions.

Let me narrow it down for your bathroom

One detail would help most: What is the maximum front-to-back length you can accommodate, measured from the wall behind the toilet to the front of the bowl?

1. Available toilet depth

Under 26 inches

26–28 inches

29–31 inches

31+ inches

Not sure yet

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2. Bidet preference

Add a separate bidet seat

Toilet with bidet already included

Either option

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3. Budget for the toilet

Under $500

$500–$1,000

$1,000+

[Find the best fits]

Finding a one-piece toilet that is compact, chair-height (ADA/Comfort Height), and bidet-seat-friendly can be tricky because one-piece designs often limit clearance behind the seat.

Top models meeting these criteria feature optimal dimensions and bidet compatibility:

1. TOTO Aquia IV One-Piece Elongated (Universal Height)

• Why it works : It features a skirted, compact modern design and stands at a chair-height rim measurement of roughly 1 6 1 8 i n c h e s . It is sold in specialized TOTO WASHLET+ Aquia IV Systems that cleanly conceal bidet connections, or it can accept standard slim electronic bidet seats.
• Dimensions : Space-saving dual-flush footprint with a 12-inch rough-in.[1][2][3]

1. Hanikes Compact Elongated One-Piece Toilet Combo

• Why it works : Built with a comfort chair-height design to make sitting and standing easier. It utilizes a compact elongated bowl, meaning it gives you the leg comfort of an elongated shape while occupying the tight projection space of a round bowl.
• Bidet compatibility : Often comes packaged with a matching low-profile bidet attachment, but the standard bolt spread accommodates various aftermarket bidet seats as long as the rear tank clearance is measured.

1. TOTO Carlyle II / Carolina II (Comfort Height)

• Why it works : TOTO's skirted one-piece transitional toilets offer a comfortable ADA-compliant seating height (17.25 inches with seat) and a trim tank profile.

• Bidet compatibility : Fully compatible with TOTO Washlet electronic bidet seats, creating a seamless look without exposed cords.

• Watch the "French Curve" : Some one-piece toilets curve sharply where the tank meets the bowl (a French curve), which blocks electronic bidet seats with a rigid bottom flange. Look for flat-backed or specifically compatible "WASHLET+" systems if you want a guaranteed flush fit.

• Measure Tank Clearance : Measure the distance from the center of the toilet bolt holes to the front face of the tank. Compact one-piece models leave less than 1.5 inches of clearance sometimes, requiring an ultra-slim profile bidet seat (such as the *Brondell Swash Thinline * or *Alpha UX Pearl * ) rather than bulky traditional units.

Would you like to share your approximate budget or whether you prefer an integrated electronic bidet system versus an aftermarket bidet seat you already own? I can narrow down the exact measurements and compatibility.