30 Inch Electric Cooktop Sizing: Will It Fit Your Countertop Cutout?

A 30-inch electric cooktop rarely needs a 30-inch countertop opening — most models require a cutout roughly 28 1/2 to 28 15/16 inches wide and 19 1/4 to 20 inches deep, so the exact installation sheet for your model decides the fit.

Buy the cooktop first and measure the counter second, and you can end up with a $1,000 slab of granite that no longer has a home. The number on the box — 30 inches — describes the glass surface width, not the hole it drops into. Installers who skip that distinction are the ones who cut a counter too wide, then discover the cooktop’s edge won’t cover the gap.

Getting it right takes three measurements and two clearances, all printed in the model’s own instructions. Here’s how to read those numbers before anyone touches a saw.

How To Measure Your Countertop Cutout For A 30-Inch Cooktop

Measure the existing opening, not the counter, and compare it against your specific model’s cutout dimensions — a cutout that’s “close” is a cutout that fails.

Pull the tape across the opening at its narrowest point (width) and again front to back (depth). Those two numbers are what you match against the specification sheet. Same nominal size, different holes.

That’s the trap. “30-inch cooktop” is a category, not a dimension. Published cutouts from major manufacturers land across a band of roughly 28 1/2 to 28 15/16 inches wide, and depth varies just as much. A counter cut for one brand’s cooktop often won’t accept another brand’s unit without rework.

• Width: narrowest point of the opening, side to side.
• Depth: front edge of the opening to the rear edge.
• Counter front clearance: Bosch requires at least 2 1/4 inches from the counter front; some sheets call for a minimum flat surface depth behind the cutout.
• Rear wall clearance: Bosch lists 2 inches minimum to the wall behind the cooktop.

If the opening is already too large, a filler strip or a different model is the fix — not a bigger cooktop. If it’s too small, the counter has to be cut again, which is why the model number belongs in your hand before the first measurement.

Clearances And Cabinet Rules People Get Wrong

Cutout dimensions alone don’t guarantee a safe install — the space around the cooktop has its own required distances from cabinets, walls, and anything overhead.

If that cabinet bottom is protected with the specified flame-retardant millboard and sheet steel, the minimum drops to 24 inches.

These aren’t suggestions. A cooktop installed too close to unprotected cabinetry puts sustained heat against combustible material, and the installation sheet is what your inspector or installer will follow. Boxed-in clearance also affects how much room you have to drop the unit into the opening without fighting the counter edge.

One more check worth doing before you order: confirm the cutout and clearances for the exact model you want. Once you’ve matched the numbers, our tested roundup of the best 30-inch electric cooktops that fit standard cutouts is a useful next stop.

The Bottom Line: Model Specs Beat Nominal Sizing

Nominal cooktop width tells you almost nothing about whether a unit fits your counter. The cutout width, cutout depth, and the clearances to the front edge, rear wall, side walls, and overhead surfaces decide it — and all four come from one place: the installation instructions for that specific model.

Two cooktops, same “30-inch” label, different openings. Verify the model sheet before the counter gets cut. For reference, Bosch’s own product documentation at Bosch’s NET8069UC spec sheet is the kind of source to check against.