Comfort-height (sometimes called "right height," "chair height," or ADA-height) toilets sit at 17–19 inches from floor to seat top, vs. the traditional 15-inch standard. The two extra inches make sit-down and stand-up dramatically easier for adults over 5'8" tall, anyone over age 50, anyone with knee, hip, or back issues, and anyone recovering from surgery. For most households, comfort height is the default modern choice — it's the height of a standard chair, and that's the ergonomic target. The market has shifted so heavily that finding a NEW standard-height toilet at the major US retailers (Home Depot, Lowe's, Ferguson) is getting harder; most current models default to comfort height with standard height treated as a special-order variant.
There's one important exception: children's bathrooms and homes with small children as primary users. A 17–19 inch comfort-height seat is too tall for a child under 4 — their feet dangle, they're prone to falling backward, and they can't easily get on and off without a step stool. If you're outfitting a kid-primary bathroom, stick with standard height (15 inches) and let them transition to comfort-height in the main household bathroom as they grow.
The technical execution of comfort height varies. Kohler's "Comfort Height" line (Cimarron, Bancroft, Adair, Elliston, Devonshire) uses a 17.25-inch floor-to-rim with a 16.5-inch seat top — solidly within ADA range and comfortable for most adults. American Standard's "Right Height" line (Cadet 3 Right Height, Champion 4) targets a similar 17-inch rim with a slightly taller 16.75-inch seat. TOTO's comfort-height variants (Drake, Carlyle II, Aimes — all listed as "Universal Height") land at a 17-inch rim. DeerValley, Swiss Madison, and most newer modern brands default to comfort height across their entire toilet catalog. If you're shopping a US big-box store and the toilet doesn't specify standard vs. comfort height, it's almost certainly comfort height — the industry has standardized.
The most common comfort-height regret is from buyers who didn't try sitting on the toilet in the showroom. Two extra inches sounds trivial, but the change in knee-flex angle is noticeable, especially for shorter users. If you're under 5'4", visit a Home Depot or Ferguson showroom and try sitting on both a 15-inch and 17-inch model before buying — for some users, comfort height feels like sitting on a stool with feet dangling. For users over 5'8", comfort height is universally preferred over standard height in informal surveys, by 90%+ margin.
The picks: the Kohler Cimarron Comfort Height ($329–$429 two-piece, $549 one-piece) is the broad-market best pick — universally available, well-engineered AquaPiston flush, easy parts availability if anything ever needs service. American Standard Cadet 3 ($269–$359) is the value pick. Kohler Bancroft and Devonshire are the upmarket designer picks at $479–$599. For modern aesthetics, DeerValley DV-1F571 and Delta Hatcher both deliver comfort height in skirted-trapway styling under $400.