The key points
- Nominal cooktop width and required cutout are different measurements.
- A suitable opening must also provide support and required clearances.
- Let qualified trades confirm access, services and benchtop changes.
Separate the measurements on the drawing
A cooktop drawing usually distinguishes its overall surface, the body below the benchtop and the hole required for installation. These measurements serve different purposes. A glass edge covering an opening does not prove the chassis will fit, and a chassis fitting through the hole does not establish the required support around it.
Read the drawing's labels, units and any permitted dimension range. Note corner-radius requirements and whether the proposed appliance is designed for surface mounting or a particular flush installation. Avoid scaling measurements from a photograph or assuming a similar-looking product uses the same cutout as the one currently installed.
Collect information without dismantling the appliance
Record the current model number, benchtop material and thickness, visible surface dimensions, surrounding cabinetry and the appliance beneath. Photograph the overall area and any safely visible labels. If the cutout cannot be measured without removing a connected cooktop, have the appropriate tradesperson handle that stage rather than disconnecting it yourself.
Include nearby walls, splashbacks, drawers and the rangehood in the brief. The installer needs to check spaces around and below the appliance, not just the opening. Drawer contents, ventilation provisions and an oven beneath the cooktop can affect the suitability of a replacement even when its top looks like a close match.
Have the fit confirmed before benchtop work
Supply the proposed model's complete installation instructions to the installer and, where needed, a qualified benchtop specialist. Ask them to confirm the opening, support, clearances and material suitability together. A larger hole is not automatically an improvement: it may leave insufficient support or create work that another cooktop cannot conceal.
Gas type and electrical requirements also belong in this conversation. Bosch's installation guidance advises checking the gas supply type before purchase. A licensed gasfitter must assess gas compatibility and connections, while a licensed electrician assesses electrical work. Keep these checks separate from a visual judgement that the appliance looks the right size.
Create a clear purchasing record
Make a small comparison sheet with each shortlisted model, overall size, required cutout and any unanswered installation questions. Label measurements as confirmed or awaiting access. This prevents an estimate from being mistaken for an actual measurement when a retailer, cabinetmaker and installer are working from the same information.
At Value House, match the model on the listing to the manual and ask about the specific unit's condition and included mounting parts. Warranty details vary by listing. Confirm the installation plan before arranging pickup by appointment, especially when collection and benchtop work need to happen on different days.
Before you buy
- Record the current model and benchtop details.
- Obtain the replacement installation drawing.
- Have inaccessible measurements confirmed professionally.
- Agree the fit before ordering benchtop work.
Sources & further reading
Prepared with AI assistance using the manufacturer and Australian guidance linked below. Check the exact model’s documentation when planning a purchase or installation.
