D-shaped toilets occur in older bathrooms and modern wall-hung or back-to-wall installations. The outline helps describe the bowl, but does not identify its exact range. A replacement seat must match the model and version, not just a similar photograph.
Recognising the D profile
Viewed from above, a D-shaped outline usually has a straighter rear and a curved front. Corners, proportions and the inner opening vary. This is a descriptive category, not a universal fitting standard.
D-shaped toilet seats: ranges and editions
Clodia · Dolomite
Clodia has a distinctive stepped upper surface. Check the seat contact points and buffers as well as its outline; material alone does not confirm the fit.
Esedra · Ideal Standard
Esedra has a broad upper surface and has also been offered in back-to-wall configurations. Check access to the fixings and the exact mounting system.
Sfera · Catalano
Early Sfera has a slightly curved rear. Identify the edition before choosing a replacement: the family name alone is insufficient.
Sistema Sfera · Catalano
The redesigned Sfera changes rear corners, proportions and fixings. Some versions have a 22 cm fixing-centre distance; confirm the particular version and current technical drawing.
Happy D · Duravit
Happy D expresses its outline in its name. A historical configuration has fixing centres around 21 cm; do not treat that figure as a universal identification rule.
Open Space · Globo
Open Space includes different configurations, including Concept 49.36. Confirm the full variant rather than assuming every seat in the family is interchangeable.
Link · Flaminia
Link combines a straighter rear and rounded front. Check the exact bowl configuration, mounting and the features of the selected original or dedicated seat.
Serie 83 · Astra
Serie 83 illustrates a longer, narrower D profile. Historical figures around 48–49 cm long and 35 cm wide are range references, not standard D-seat dimensions.
Checks before ordering
Identify brand, range and edition first. Compare the rear profile, steps, contact points, length, width and fixing centres using the product’s measuring convention. Check whether mounting is from above or below. If the old seat was an approximate replacement, do not rely on it as the only template.
Materials and hinges
Original, dedicated and compatible are different classifications. Coated wood, MDF and thermoset materials do not establish fit. Confirm soft-close or quick-release separately. A photograph cannot confirm an older ceramic colour. If the model is uncertain, request identification before ordering; photos and measurements support that service.
See the general guide to toilet-seat shapes →
D-shaped toilets, D-shaped toilet seats