How to tell if your toilet bowl is round or elongated.
Older or basic toilets are round. The inside of the toilet bowl is usually about 11 inches around. More modern or deluxe toilets have an elongated bowl that is about 2 inches longer than it is. It's a noticeable difference. If you're still wondering, you can measure from the two mounting bolts at the seat hinge, to the very front of the toilet bowl. That measurement will be about 16 1/2 inches if the bowl is round, and 18 1/2 inches if your bowl is elongated.
1 PIECE TOILET - A toilet sculpted into a seamless unit,
and has no crevices between the tank and bowl.
2 PIECE TOILET - This type of toilet has a separate tank
and bowl which are bolted together upon installation