Bidet attachments are designed to be compatible with most standard toilet models. However, compatibility can vary based on the specific design and dimensions of the toilet. Standard bidet attachments typically fit well with two-piece toilets, where the tank and bowl are separate. Challenges can arise with some one-piece toilets or toilets with a non-standard shape or size. It's always recommended to check the specifications of the bidet attachment and compare them with your toilet's design and dimensions to ensure a proper fit. In cases of unique or non-standard toilets, specialized bidet attachments might be necessary.