ADA-Height or Comfort-Height toilets are typically around 2” taller than their standard counterparts. The official requirement is 17”-19” to the top of the seat. Elongated toilets are typically around 2-3” longer from the back of the tank to the front of the bowl, but this varies based on the manufacturer. Here is a comparison of the specifications for a few different Kohler toilets:
The Kohler Wellworth Elongated-Bowl is 14 ½” tall from floor to rim without the seat. It is 30” long from the back of the tank to the front of the bowl.
The Kohler Wellworth Round-Bowl is 27 ½” long from the back of the tank to the front of the bowl.
The Kohler Cimarron Elongated-Bowl (ADA Compliant) is 16 ½” tall from floor to rim without the seat. It is 28 ¾” long from the back of the tank to the front of the bowl.
The Kohler Cimarron Round-Bowl (ADA Compliant) is 26 ⅞” long from the back of the tank to the front of the bowl.