Toilet Seat Sizes and Compatibility Guide for Bidet Seats

Most households assume that upgrading to a bidet seat is difficult because toilets come in many shapes and sizes. In practice, almost every modern toilet follows a predictable pattern that makes compatibility easier than expected.

Two measurements determine nearly everything: (1) The shape of the bowl and (2) Distance between the mounting holes.

Once these are clear, selecting a bidet seat becomes a straightforward process.

• Elongated bowls measure longer from the seat bolts to the front rim.
• Round bowls are shorter and more compact, often found in small bathrooms.
• Mounting holes typically sit about five and a half inches apart.
• A proper fit depends on bowl shape and bolt spacing, not the toilet brand.
• Most premium bidet seats are designed for elongated bowls.

Elongated vs Round: How to Tell the Difference

Measuring from the seat bolt holes to the front edge of the bowl confirms the shape. About eighteen and a half inches indicates elongated, while roughly sixteen and a half inches indicates round.

Which Bidet Seats Fit Your Toilet

Bidet seats for elongated toilets fit most mainstream brands including TOTO, Kohler, American Standard, and similar models. Round bowls remain common in older homes or compact bathrooms.

A few toilets require closer attention. Some high-end one-piece units use a French curve design where the tank and bowl blend into a continuous front profile. Certain skirted toilets also require an alternate mounting bracket.

Shop Compatible Bidet Seats

Browse the full bidet seat collection at MajesticFlush.com, where each model lists required measurements so compatibility stays clear before installation.