New What Is The Standard Size Of A Toilet Background. Standard toilet rough in (common rough in sizes) the standard toilet rough in is 12. There really is no advantage to this size, unless your toilet has a three inch drain hole opening in the bottom.
This information can be found on the toilet's specification sheet.
This is the size of the flange opening and outlet. Standard height toilet from the 19 century when the first flushing toilet was introduced, then came the standard height wash sets. The standard toilet seat size is based on the type of toilet you own. The standard size is still great for the majority of people, it really is just a matter of preference.