How to Measure a D-Shape Toilet for a Bidet Seat (Step-by-Step)

If you are upgrading your bathroom with a sleek, non-electric bidet seat like the Conor Elara D-Shape, getting the right fit is the difference between a luxury experience and an awkward, unstable seat.

Modern Australian bathrooms love the clean, flat-backed silhouette of a D-shape toilet pan. However, because these pans are wider at the back corners than standard oval bowls, guessing the size won't work.

Follow this quick 4-step measurement guide to ensure your new D-shape bidet seat aligns perfectly with your porcelain bowl.

Quick Answer: Standard D-Shape Bidet Measurements

To fit a standard Australian D-shape bidet seat (like the Conor Elara), your toilet pan typically requires:

• Bolt Hole Distance: 
• Bowl Length: (from bolt holes to front tip)
• Bowl Width: at the widest point

The 4 Vital D-Shape Toilet Measurements

Before you grab your tape measure, completely remove your existing toilet seat so you are measuring the bare porcelain pan.

      Step 1: Measure the Bolt Hole Distance (A)

Locate the two mounting holes at the back of your toilet pan where the seat attaches. Measure the distance from the center of one hole to the center of the other.

• Target Measurement: Most modern D-shape bidets feature adjustable plates that fit a spacing between and .

Step 2: Measure the Bowl Length (B)

Place your tape measure directly between the two bolt holes, and extend it straight down the middle of the toilet to the very front outer edge of the porcelain rim.

• Target Measurement: For an elongated D-shape profile like the Conor Elara, you generally want a length of to . If your toilet is shorter than , it may be a compact round pan rather than a true D-shape.

Step 3: Measure the Bowl Width (C)

Find the widest point of your toilet bowl's rim (usually right across the middle section) and measure from the outer left edge to the outer right edge.

• Target Measurement: A standard D-shape pan usually measures between and wide.

Step 4: Check the Clearance (The Tank Distance)

Measure from the center line of the bolt holes backward to the front face of the cistern (toilet tank) or the wall. Non-electric bidets have a slightly thicker rear housing to protect the internal water valves, so they need a little breathing room.

• Target Measurement: You typically need at least of flat clearance behind the bolt holes so the seat lid can open fully without hitting the tank.

Crucial for Australian Bathrooms: Top-Fixing vs. Bottom-Fixing

When buying a D-shape bidet seat, you must check how your current toilet is built.

• Back-to-Wall Toilets (Top-Fixing): If your toilet pan goes all the way to the wall and the porcelain sides are completely enclosed, you cannot reach underneath to tighten a traditional nut. You must use top-fixing bolts (expansion rubber plugs that screw directly into the bolt holes from above).
• Open-Sided Toilets (Bottom-Fixing): If you can reach your hand underneath the back of the toilet bowl to spin a plastic nut onto the thread, your toilet uses bottom-fixing.

Why choose the Conor Elara?

The Conor Elara D-Shape bidet toilet seat comes complete with universal premium top-fixing expansion kits, making it compatible with modern, fully-skirted Australian back-to-wall toilet suites.

Why a Precise D-Shape Fit Matters

Installing a standard round or oval bidet seat onto a D-shape toilet pan causes two major problems:

1. The Overhang Aesthetic: The square rear corners of your porcelain pan will stick out from underneath the seat, ruining the clean lines of your bathroom.
2. Stress Fractures: If the bidet seat's support pads do not sit squarely on top of the porcelain rim, the plastic seat will flex every time you sit down, eventually causing the hinges or the seat itself to crack under weight.

Ready to upgrade your bathroom hygiene with a perfect fit?

Check out the Conor Elara D-Shape Non-Electric Bidet Seat—specifically engineered for premium Australian design, 100% WaterMark certified reliability, and seamless DIY installation.