In the plumbing world, most toilets are one of two sizes: "standard" and "elongated".  A standard size toilet, also referred to as "round", has historically been the most common in American homes.  However, the elongated size toilet, sometimes called "oblong", is often installed in homes being built today thanks to its more luxurious larger size. 

To determine which size toilet you have, and thus which size toilet seat will fit your toilet, grab a measuring tape.  Measure the length of the toilet bowl from the hinge post holes to the front rim. 

If the length is about 16-17 inches, a standard round toilet seat will fit your toilet.  If the length is 18-19 inches, an elongated/oblong toilet seat will fit. 

Both toilet seat sizes have a width of  about 14.5 inches, and in the United States, the distance between the hinge post holes is about 5.5 inches.

View our STANDARD SIZE Toilet Seats          View our ELONGATED SIZE Toilet Seats