Toilet buying guide: rough-in, shape, height and flush

Most toilets look alike in a catalog, and most of the differences that matter are measurements. Get the rough-in and the bowl shape right and a new toilet is a quick swap; get them wrong and it will not sit against the wall.

1. Measure the rough-in first

The rough-in is the distance from the finished wall to the center of the floor bolts. 12" is standard; some older homes have 10" or 14". Buy a toilet with the same rough-in as your drain. The rough-in checker walks you through it and checks clearances.

2. Round or elongated bowl

An elongated bowl is about 2" longer and more comfortable for most adults. A round bowl saves space in a tight powder room. Codes want 21" of clear space in front of the bowl and 15" from the toilet centerline to a wall or fixture at the side.

3. Height

Comfort-height (also called right-height or chair-height) toilets have a seat about 17" to 19" from the floor, close to a dining chair, and are easier to sit down on and stand up from. Standard toilets are about 15". Shorter people and children sometimes prefer standard height.

4. One-piece or two-piece

• One-piece: tank and bowl molded together, no seam to clean, usually a sleeker look and a higher price.
• Two-piece: separate tank and bowl, lighter to carry up stairs, easier on the budget.
• Wall-hung: the tank hides in the wall; saves floor space and looks great, but it is a remodel item, not a swap.

5. Flush performance and water use

Look for the WaterSense label (1.28 gallons per flush or less) and a high MaP score, which measures how much waste a toilet clears in one flush. Dual-flush models use less water for liquids. A skirted (concealed trapway) bowl is easier to clean around.

6. Bidets and smart seats

A bidet seat adds warm-water washing to most standard toilets and needs a GFCI outlet within reach of the toilet for heated models. If you might want one, have the outlet added when the bathroom is updated.

Common questions

What is the standard toilet rough-in?

12 inches from the finished wall to the center of the floor bolts.

Is an elongated toilet better?

For most adults, yes: it is more comfortable. A round bowl is better in a very small powder room.

What is a comfort height toilet?

A toilet with a seat about 17" to 19" from the floor, easier to sit on and stand up from than the standard 15".