How to Measure Your Toilet for a Raised Seat or Bidet Seat: Elongated vs Round, Bolt Spacing and Tank Clearance

Most fit problems with raised toilet seats and bidet seats are not quality problems. They are measurement problems. A seat made for an elongated toilet will not sit right on a round toilet, a seat that needs power will not help a bathroom with no outlet nearby, and support arms need side clearance to be useful. Measure first, order second.

1. Elongated or round? Start with bowl shape

Look at your toilet bowl from above. An elongated bowl is longer front-to-back and more oval. A round bowl is shorter and more circular. This matters because the Marine Dana All-in-One Toilet Safety System and the Smart Heated Bidet Toilet Seat are both designed for most elongated toilets, not round toilets. If your bowl is round, do not guess that an elongated seat will fit.

2. Measure bolt-to-front length

• Find the two seat bolts at the back of the toilet, where the seat hinges.
• Measure from the centre of those bolts straight to the front edge of the bowl.
• Write the number down, in inches, and compare it with the fit guide and technical drawing on the product page.

Do not measure the lid, the seat, or the whole toilet including the tank. The bowl measurement is the one that decides whether the seat shape matches.

3. Check tank clearance and mounting area

Next, check the space behind and around the bowl:

• Tank clearance: is there room between the back of the seat and the tank or wall for the seat to sit flat and for its hinges and controls?
• Mounting area: are the seat bolts accessible, and is the top of the bowl flat enough for the seat to sit securely?
• Water supply: for a non-electric bidet wash, is the toilet water supply valve accessible? For a heated bidet seat, is there also a power outlet near the toilet?

If tank clearance is tight, take a photo of the side profile of your toilet and email it with your measurements to support@marinedana.com before ordering.

4. Check side clearance for support arms

Support arms are only helpful if they can be used. Measure from the centre of the toilet to nearby walls, cabinets, tubs and fixtures on both sides. Leave enough room for hands to grip the arms and for the user to sit and stand without hitting a fixture. Our Toilet Safety System Buying Guide for Seniors and Caregivers walks through this check in more detail.

5. Check power and water, not just shape

Use this quick summary before you choose:

• No outlet nearby: a non-electric bidet attachment, from $57.50, or the non-electric wash in the All-in-One system, from $298, may fit better than an electric seat.
• Outlet nearby and elongated toilet: a heated bidet seat, from $169, adds instant warm water, an adjustable heated seat and warm-air drying.
• Support needed as well as hygiene: the All-in-One system combines a raised seat, side support arms and a non-electric bidet wash in one setup.

6. A 2-minute measuring checklist to save

1. Bowl shape: elongated or round?
2. Bolt-to-front length, in inches.
3. Tank clearance and mounting area: flat, accessible, no obstruction?
4. Side clearance for support arms, if you plan to use them.
5. Water supply access, and power outlet access if you want a heated seat.

Still unsure? Read the Product Fit, Installation, Shipping and Returns FAQ, and email your toilet model and measurements before purchasing. Follow the supplied manual and use a qualified installer when needed.

This is general product and measurement information, not medical advice. If transfer safety, balance or installation is uncertain, ask a qualified clinician, occupational therapist, plumber or installer.