D-Shape vs O-Shape Bidet Seat: Which One Fits Your Toilet?

If you’re shopping for a non-electric bidet toilet seat in Australia, the very first question to answer isn’t which brand or which features you want — it’s what shape is your existing toilet bowl. Bidet seats aren’t one-size-fits-all, and fitting the wrong shape means a wobbly seat, gaps around the edges, or a return trip to the post office.

In this guide, we’ll break down the difference between D-shape and O-shape bidet seats, using the Conor Elara Non-Electric Bidet Seat range as a real-world example, so you can confidently choose the right seat for your bathroom.

Why Toilet Shape Matters for Bidet Seats

Standard toilets in Australia generally come in two bowl-and-seat profiles:

• D-shape (elongated/oval-pointed) — the seat has a slightly squared-off, elongated front that comes to a gentler point, resembling the letter “D”.
• O-shape (round/oval) — the seat has a more rounded, compact oval front, resembling the letter “O”.

A bidet seat is built to match the exact outline and mounting hole spacing of one of these two shapes. Buying the wrong one means the seat may not sit flush on the bowl, the nozzle position may be off-centre, and the soft-close hinges may not seal properly — all of which affect both comfort and hygiene performance.

Before buying, measure your current toilet seat or refer to your toilet manufacturer’s spec sheet so you know which category your bowl falls into.

Meet the Conor Elara Non-Electric Bidet Seat

The Conor Elara is a WaterMark-certified, non-electric bidet seat available in Australia in both D-Shape and O-Shape versions, with left or right water inlet options. Both versions share the same core technology — they simply differ in their outer shape and dimensions to suit different toilet bowls.

Here’s how the two compare side by side:

As you can see, the price, materials, hygiene features, and warranty are identical — the only real differences are in the outer dimensions and the silhouette of the seat itself.

D-Shape Bidet Seats: Best For

A D-shape non-electric bidet toilet seat is designed for toilets with an elongated, slightly pointed front — the most common profile found in many modern Australian bathrooms, particularly newer builds and renovations.

Choose D-shape if:

• Your current toilet seat has a longer, more tapered front edge
• You’re replacing an existing D-shape seat and want a like-for-like fit
• You prefer a slightly larger seating surface (the D-shape Elara has a marginally longer overall length at 48.5 cm)

The D-shape Conor Elara comes with the same self-cleaning nozzle, soft-close lid, and adjustable single-lever spray as the O-shape version, so you’re not compromising on functionality — only on the outer shape to match your bowl.

Shop the Conor Elara D-Shape Non-Electric Bidet Seat

O-Shape Bidet Seats: Best For

An O-shape (oval/round) non-electric bidet seat suits toilets with a more rounded, compact bowl outline — common in older bathroom suites and some compact or space-saving toilet designs.

Choose O-shape if:

• Your current seat has a rounder, shorter front profile
• Your bathroom has a more compact toilet footprint
• You’re matching an existing O-shape suite during a like-for-like replacement

The O-shape Conor Elara is marginally shorter and slightly lower in height (8.5 cm vs 9 cm) than the D-shape version, but offers the exact same hygiene features, WaterMark certification, and 1-year warranty.

Shop the Conor Elara O-Shape Non-Electric Bidet Seat

How to Check Which Shape You Need

If you’re not sure whether your toilet is D-shape or O-shape, try one of these quick checks:

1. Look at your current seat from above. A longer, tapered front that narrows to a gentler point usually indicates D-shape. A shorter, more rounded front usually indicates O-shape.
2. Measure the length from the centre of the mounting holes (at the back) to the front tip of the seat. Compare this against the dimensions listed above — 48.5 cm for D-shape, 47.6 cm for O-shape.
3. Check the manufacturer’s documentation for your existing toilet suite, if available.
4. When in doubt, contact the seller before ordering — Conor’s support team can help confirm fit based on photos or measurements of your existing bowl.

Left Inlet vs Right Inlet: Don’t Forget This Step

Whichever shape you choose, both the D-shape and O-shape Conor Elara are available with a left or right water hose inlet. This refers to which side the flexible water hose connects to when you’re facing the bidet seat. Check where your toilet’s water supply line currently sits (or where you’d like it positioned) before placing your order, since this affects how neatly the hose routes to your wall connection.

Shared Features Across Both Shapes

Regardless of which shape suits your toilet, both versions of the Conor Elara non-electric bidet seat include:

• WaterMark certification (WMK26172) for compliant use in Australian plumbing
• Duroplast construction that resists scratches, stains, and discolouration
• Soft-close seat and lid to prevent slamming
• Self-cleaning nozzle that rinses automatically before and after each use
• Dual nozzles for rear cleansing and feminine hygiene
• Single-lever spray control for adjustable water pressure — no electricity required
• Installation kit included, with all hardware, hose, and instructions
• 1-year warranty and 30-day money-back guarantee

Installation is straightforward, but because the seat connects to your water supply, Australian plumbing regulations require the connection to be completed by a licensed plumber.

Final Verdict: D-Shape or O-Shape?

There’s no universally “better” option between D-shape and O-shape bidet seats — the right choice comes down entirely to the shape of the toilet bowl you already have. Both the D-shape and O-shape Conor Elara non-electric bidet seats deliver the same hygiene performance, build quality, certifications, and value at $159, so once you’ve confirmed your toilet’s profile, you can choose with confidence.

• D-shape toilet? Go with the Conor Elara D-Shape Non-Electric Bidet Seat
• O-shape toilet? Go with the Conor Elara O-Shape Non-Electric Bidet Seat

Frequently Asked Questions

Is a D-shape bidet seat universal? 

No. D-shape seats are designed to fit D-shape toilet bowls only. Fitting a D-shape seat to an O-shape toilet (or vice versa) will result in a poor fit and may affect nozzle alignment.

Are non-electric bidet seats easy to install? 

The installation kit makes the process straightforward, but because the unit connects to your home’s water supply, a licensed plumber is required to complete the connection in line with Australian plumbing regulations.

Do non-electric bidet seats need power? 

No. Both the D-shape and O-shape Conor Elara operate purely on your home’s existing water pressure (recommended range: 0.07–0.08 MPa), with no electricity required.

What’s the difference in price between D-shape and O-shape? 

There is no price difference — both the Conor Elara D-Shape and O-Shape non-electric bidet seats are currently $159 (down from $249), inclusive of GST and free shipping across Australia.

Can I return the seat if it doesn’t fit my toilet? 

Yes. Both versions come with a 30-day money-back guarantee on unused items, so it’s worth double-checking your toilet’s shape and measurements, but you’re covered if there’s an issue.