There are 3 main things you want to check to see if a Toto bidet will fit your toilet.
1. Is the toilet round or elongated?
2. Is there at least 1.75 inches between the seat mounting holes and the toilet tank?
3. Is there an electrical outlet within 3ft of the back of the toilet?
If you know the answer #1, and answer "Yes" to 2 & 3, then any Toto Bidet seat will fit your toilet.
Of course, you can always call in and we'd be happy to double check for you.