Total newbie question, sorry!

What's a 12" rough-in? I want/need to replace the 15 year old generic toilets in our house with Toto Ultramaxes, but need to be sure that they can work with our existing plumbing. What do I measure to ensure that the new ones (with 12" rough-in) can be bolted in place without floor surgery.

Thanks for any suggestions.

Look at p 2 of this sheet. Look at the 12 in the lower left of the diagram.

https://terrylove.com/pdf/MS854114S%20MS853113S.pdf

measure from your wall to the bolts on your existing toilets.

Usually, the bolts are located at the middle of the flange, so that will be a good measurement - technically it's to the middle of the drain to the wall. Note, it's to the wall, not the baseboard. Depending on the toilet, there will usually be some gap behind the toilet, so if it is less than 12", it might still fit...depends on the specific toilet you choose.

Thank you all. The bolts are 12", so I'll go with that suggestion.