Toilet Dimensions Guide: Width, Depth, Height Charts

Toilet listings rarely surface the one number that will make or break your purchase. A spec sheet might show the overall height but omit the bowl height, list total depth but not clarify whether the tank is included, or quote a rough-in without explaining what happens if yours is different. A toilet that lands wrong over the drain, hits the door swing or crowds the vanity is a return trip, a restocking fee and a plumber's second visit. The goal of this guide is to make that outcome impossible by giving you every relevant dimension, explained in plain terms, before you ever look at a product page.

Everything here is sourced from published manufacturer specifications, independent MaP (Maximum Performance) flush-test data, EPA WaterSense certification records and the patterns that aggregate consistently across verified owner reviews. We do not install or test toilets ourselves. Models referenced throughout include the TOTO Drake, TOTO Drake II, TOTO UltraMax II, TOTO Aquia IV, Kohler Highline, Kohler Cimarron, American Standard Champion 4, American Standard Cadet 3, Woodbridge T-0001, Swiss Madison and Gerber. Once you have your measurements, our roundup of the best flushing toilets matches top performers to your space.

What are the standard toilet dimensions?

These ranges exist because toilet dimensions vary by bowl shape, one-piece versus two-piece construction, tank style and comfort-height versus standard-height designation. A compact one-piece like the TOTO UltraMax II comes in at 28.5 inches deep and 29.5 inches tall, while a taller two-piece comfort-height model like the Kohler Highline Comfort Height stretches to 31 inches tall with a similar footprint. Width is the most consistent measurement because tank width drives it, and most tanks are 13 to 20 inches across.

Recommended toilets in this guide

TOTO Drake II (CST454CEFG)

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TOTO UltraMax II (MS604114CEFG)

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Woodbridge T-0001

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The table below gives real published dimensions for six of the most widely purchased toilets in the United States, drawn directly from manufacturer specification sheets. Use it to anchor your planning before measuring your own bathroom.

Notice that depth ranges from 28.25 to 30.25 inches across these popular models, a two-inch spread that can decide whether a door clears, a vanity fits beside it, or a closet wall leaves enough room. Height from floor to tank top runs 28.75 to 31 inches, which matters if you are mounting a shelf, a medicine cabinet or a towel bar behind or above the tank. Bowl height (floor to seat top without the seat) is the number that determines comfort, especially for users with mobility concerns.

How do you measure toilet depth correctly?

When measuring available floor space for depth, start at the finished back wall (not the baseboard) and measure toward the door, vanity or any edge that constrains the toilet's footprint. Your usable depth is that measurement minus any clearance you want for walking past. Building codes in most jurisdictions require at least 21 inches of clear space from the front of the toilet bowl to any wall, door, obstruction or fixture directly in front. The International Residential Code (IRC) specifies a 21-inch minimum; some local codes require 24 inches, and the ADA (Americans with Disabilities Act) guidelines call for 60 inches of clear floor space in front of an accessible toilet.

For a standard bathroom with a 12-inch rough-in, the calculation looks like this: measure from the back wall to the front obstruction, subtract your front clearance requirement (21 inches minimum), and the remaining number is your maximum allowable toilet depth. A bathroom that is 60 inches from wall to tub gives you 60 minus 21 = 39 inches of usable depth, which fits any standard toilet. A powder room that is 48 inches deep gives you 48 minus 21 = 27 inches, which means you need a round-bowl or compact elongated toilet, not a standard elongated model.

The TOTO Entrada is a frequently recommended round-bowl model that comes in at about 26.5 inches deep, making it one of the most space-efficient choices that still carries EPA WaterSense certification at 1.28 GPF. If a round bowl feels cramped but your room cannot fit a standard elongated model, the American Standard Cadet 3 Compact Elongated is engineered to match the depth footprint of a round bowl while retaining an elongated seat profile.

What is the correct toilet height for comfort and accessibility?

Height terminology is confusing because brands use it inconsistently. "Bowl height" refers to the measurement from the floor to the top of the porcelain bowl rim, not the seat. Seat thickness adds roughly 0.5 to 1 inch, so the sitting height (floor to top of seat) is about an inch higher than the bowl height figure. When evaluating whether a toilet is right for a user with mobility concerns, arthritis or joint issues, use the seat-height figure, which is bowl height plus seat thickness.

Most plumbing manufacturers now offer comfort-height versions of their flagship lines. The TOTO Drake and Drake II are both available in comfort-height configurations (designated by the "E" or "EL" in the model suffix, indicating 1.28 GPF with an elongated comfort-height bowl). Kohler uses the label "Comfort Height" explicitly in model names such as the Kohler Highline Comfort Height. American Standard calls its elevated bowl option "Right Height." Gerber uses "ErgoHeight." The underlying specification is the same across brands: a bowl height at or above 16.5 inches.

For a bathroom that will serve users of multiple generations or one user who is likely to have difficulty rising from a low seat, comfort height is the right default. If the household includes young children as primary users, a standard-height toilet may be more practical because the height is easier for small legs to manage without a step stool.

What toilet width do I need and how much side clearance is required?

Width is the least variable of all toilet dimensions, because tank width changes relatively little across standard residential designs. The practical constraint is not the toilet's width itself but the side clearance the code requires. IRC Section R307.1 requires at least 15 inches from the toilet centerline to any side wall, vanity, bathtub or other obstacle. Because the toilet centerline sits over the drain, the rough-in measurement determines where the centerline falls, and you verify clearance from that center point outward in both directions.

If your rough-in places the drain center 15 inches from the left side wall, you have exactly the minimum required clearance on that side. Most designers recommend 18 inches from centerline to wall for comfortable use, which means a bathroom needs at least 36 inches total from wall to wall to house a toilet with comfortable side access. Many bathrooms place the toilet between a wall and a vanity, so measuring clearance to both surfaces from the drain center is essential before finalizing your layout.

How does one-piece versus two-piece design affect dimensions?

The one-piece versus two-piece choice is more about aesthetics, cleaning ease and installation logistics than fitting in a bathroom. One-piece toilets like the TOTO UltraMax II and the Woodbridge T-0001 have a sleeker silhouette because there is no gap between tank and bowl, but they ship in a single heavy box (typically 90 to 120 pounds) that can be difficult to maneuver. Two-piece models like the TOTO Drake, Kohler Cimarron and American Standard Champion 4 come in two lighter boxes and can be assembled in the bathroom after the bowl is set, which makes installation much easier in tight spaces or on upper floors.

In terms of pure footprint, the differences are small. The TOTO UltraMax II (one-piece) measures 28.5 x 18.88 x 29.5 inches. The TOTO Drake II (two-piece) measures 28.25 x 19.5 x 30.13 inches. The two-piece is fractionally narrower in depth but slightly wider and taller. Both fit the same 12-inch rough-in and carry identical 1.28 GPF ratings with MaP scores of 1000 grams. For bathrooms where every inch of depth counts, neither type has a consistent advantage. The real depth savings come from bowl shape (round versus elongated) and whether the design is a compact elongated style.

What dimensions change for a small bathroom or powder room?

A half-bath or powder room that is 30 to 36 inches wide presents two challenges: side clearance from the toilet centerline to both walls, and depth clearance from the tank back to the front of the bowl. If the room is 30 inches wide and the drain is centered at 15 inches from each wall, you meet the minimum code requirement but have no margin. A 36-inch wide powder room with the drain centered gives 18 inches on each side, which is comfortable. Depth in powder rooms is often the binding constraint, because the door typically opens into the same footprint the toilet occupies.

For powder rooms and tight bathrooms, the toilet options that consistently appear in verified owner reviews as successful are: the TOTO Entrada (round, 26.5 inches deep), the American Standard Cadet 3 Compact Elongated (about 27.5 inches deep), and the Swiss Madison St. Tropez (one-piece, about 26.6 inches deep). All three carry EPA WaterSense certification at 1.28 GPF. Our guide on the best toilet for small bathrooms covers these in more depth.

How do rough-in dimensions interact with overall toilet depth?

Understanding how rough-in and depth interact helps when shopping for tight spaces. A 10-inch rough-in toilet is not 2 inches shallower overall than a 12-inch version; it is designed to sit closer to the wall with less tank depth, but its total floor footprint from wall to bowl front is very similar. The toilet that fits a 10-inch rough-in just sits with the tank closer to the wall. Our complete toilet rough-in guide covers 10, 12 and 14 inch options with specific model recommendations for each size.

Where rough-in does matter for depth is in the rear-of-tank clearance. A toilet intended for a 12-inch rough-in will position the back of its tank right against the wall when the drain is at 12 inches. If you install a 12-inch toilet on a 14-inch rough-in (using an offset flange), you get an unsightly 2-inch gap between the tank and the wall. If your rough-in is non-standard, the cleanest outcome is always a toilet designed for that rough-in distance, not an offset adapter, which adds a failure point.

Complete toilet dimensions reference chart by popular models

The table below consolidates published specifications for twelve popular toilet models across six brands. Bowl height is measured from finished floor to top of bowl rim without seat. Seated height adds approximately 0.5 to 1 inch depending on seat thickness.

A few patterns emerge from this data. First, total height is not driven by bowl height alone: the TOTO Drake has a 15.13-inch standard-height bowl yet a 30-inch total tank height, because the tank extends upward. The Kohler Cimarron has a comfort-height bowl at 16.5 inches and a 31.25-inch total height. Second, width is relatively consistent: 17 to 20 inches covers the full range of standard residential models. Third, the biggest depth spread (26.6 inches for the Swiss Madison compact to 30.25 for the Kohler Highline) is nearly four inches, which is meaningful in tight rooms.

How do you measure your bathroom to find the right toilet size?

Taking all five measurements before you shop eliminates the vast majority of return scenarios. Here is how to take each one correctly.

Rough-in: With the toilet in place, measure from the finished wall behind the tank to the center of the rear bolt caps at the toilet base. With no toilet installed, measure from the finished wall to the center of the closet flange. Round to 10, 12 or 14 inches. Our toilet rough-in measurement guide has photos of each scenario.

Available depth: Measure from the back wall to whatever is directly in front of the toilet position (door, tub, vanity, opposing wall). Subtract your minimum front clearance (21 inches for IRC, 24 inches recommended). The result is your maximum allowable toilet depth including supply line.

Side clearance: Measure from the drain center to the nearest fixture or wall on each side. You need at least 15 inches both ways. Mark the centerline on the floor with tape if it helps visualize.

Height clearance: In most bathrooms this is not a constraint unless a window sill, medicine cabinet or countertop shelf sits lower than 32 inches above the floor behind where the tank will sit. Tank tops on most two-piece models are 28 to 32 inches off the floor.

Door swing: If the bathroom door swings inward toward the toilet, stand at the toilet position and swing the door with your hand. A toilet lid open at 90 degrees typically extends 12 to 14 inches above the seat hinge point. On tight bathrooms, a soft-close seat that stops at 80 degrees rather than 90 can recover several inches of clearance.

Tank dimensions: what varies and what to check

The toilet tank is the component that most frequently causes surprises after installation because its back surface rests against or very close to the wall, and its top surface determines how high the toilet looks in the room. Two tank measurements matter beyond the height already covered: tank width and tank depth (front to back).

Tank width is essentially the toilet's overall width at the widest point, since the bowl is narrower. Standard tanks range from 13 to 20 inches wide. A 20-inch wide tank on a toilet where the drain center sits 18 inches from a side wall means the tank edge reaches 28 inches from the wall on the far side, and only 8 inches from the near wall. That 8-inch gap may or may not be enough to route a supply line and still open the shut-off valve. Always verify tank width against your side clearances, not just the centerline distance.

Tank depth (front to back) is typically 5 to 8 inches for standard gravity tanks. Pressure-assist toilets sometimes have slightly deeper or bulkier tanks because of the pressure vessel inside. This measurement matters when a window sill sits directly above where the tank will land, which is common in older bathrooms where the toilet was placed under the window to use exterior wall plumbing stacks.

Toilet seat dimensions and compatibility

Toilet seats are not universal. They come in round and elongated shapes, and within elongated there are standard and "D-shaped" profiles used by some European-influenced brands. The seat dimension that matters for fit is the bowl length: round bowls typically measure 16.5 inches from bolt holes to front rim, and elongated bowls measure 18 to 18.5 inches. A seat designed for an elongated bowl will not clip down correctly on a round bowl, and vice versa.

Seat width is less variable: most seats are 14 to 15 inches across the hinge end and 14.5 inches across the front. Bolt hole spacing is standardized at 5.5 inches center to center on virtually all North American toilets, so seat mounting is interchangeable across brands as long as bowl shape matches.

Bidet seats add meaningful height. A standard bidet toilet seat adds 2 to 3 inches to the seated height, which brings a standard-height toilet to comfort height and a comfort-height toilet to ADA territory. If seated height matters for your use case, confirm seat plus bidet seat plus bowl height before ordering a bidet.