Thirty inches: the width your appliances already chose
Reviewed September 2026 · Captivating Cabinets
Ranges are 30 inches. Cooktops are 30 inches. Wall ovens are 30 inches. Once you notice that, the ten boxes made at this width stop looking like a long list and start looking like a set of answers to a set of appliance questions — plus the cheapest item on the entire base board, which is not a cabinet at all.
Which 30-inch box goes with which appliance
Start from what is being installed, not from the cabinet catalog. The appliance is the fixed dimension; the box is the thing that adapts.
| What you are installing | What to order | Displayed price | Confirm first |
|---|---|---|---|
| Slide-in or freestanding range | No cabinet — leave the opening | — | The model's required opening; some want a fraction over 30 inches |
| Cooktop over storage | B30 or DB30-2 | $555.75 / $835.25 | How far the burner box drops below the counter, before you put drawers there |
| Wall oven, under the counter | BOC30 base oven cabinet | $598.00 | The oven's cut-out height and depth against the bay |
| Built-in or drawer microwave | BMC30 base microwave cabinet | $695.50 | The bay opening, which the listing does not publish |
| Apron or farmhouse sink | FS30 farm sink cabinet | $806.00 | The sink brand's required cabinet width — many 30-inch aprons want a 33 |
| Drop-in or undermount sink | SB30 sink base | $461.50 | The sink's minimum cabinet width; a 33-inch double will not fit |
BOC30 is the only base oven cabinet made
Not the only one at this width — the only one at any width on the base board. If you want a wall oven under a countertop, it is 30 inches wide, it is $598.00, and there is no alternative size. Everything else that houses an oven is a tall cabinet, which is a different board and a different height.
That constraint is worth knowing early, because it fixes 30 inches of your run before anything else is placed. Oven first, then the sink, then the dishwasher, then fill the rest.
The cheapest item on the base board is 30 inches wide
KD30 displays at $172.25 — less than half the price of anything else here — because it is a knee drawer, not a cabinet. It is the shallow drawer that spans the leg space in a desk or a make-up run, hanging under the top with the boxes on either side carrying it. No carcass, no doors, no shelf.
Its dimensions are not published on the listing, so if you are designing a knee hole to a specific height, confirm the drawer's depth before you set the cabinets either side. Paired with two 18-inch file drawer bases it gives a 66-inch desk run.
Two very different sinks at one width
SB30 at $461.50 is a conventional sink base: the top is open for a drop-in or undermount bowl and the doors are full height. FS30 at $806.00 is a farm sink cabinet — the front is cut away so an apron sink's face becomes part of the cabinetry, and the box is built to carry the weight.
They are not interchangeable in either direction, and the $344.50 between them is not a premium for looks; it is a different cabinet. The catch on the apron version is that a sink sold as 30 inches often asks for a 33-inch cabinet, because the apron needs bearing on both sides. Work from the sink spec sheet, always.
The mistake at this width
Measuring the range opening off the cabinet list. A cabinet run of 30 inches is 30 inches; a range that needs 30⅛ inches is not going in. The tolerance has to be designed in, usually as filler somewhere else on the wall, and it has to come from the appliance spec sheet rather than from a rule of thumb. This is the single most expensive quarter-inch in a kitchen, because by the time it is discovered the countertop has been templated.
Common questions
- What size base cabinet goes under a 30-inch cooktop?
- A 30-inch box — either the standard base at $555.75 or the two-drawer bank at $835.25. Check how far the cooktop's burner box drops below the counter before choosing the drawer version.
- Can you put a cooktop over a drawer base?
- Often, yes, but it depends on the appliance. The burner box intrudes into the top drawer, and some cooktops need more room than a standard drawer leaves. Compare the appliance's under-counter depth against the drawer before ordering.
- Do I need a cabinet for a 30-inch range?
- No. A slide-in or freestanding range fills the opening on its own. Leave 30 inches of run with no box in it, and confirm the exact opening the model requires.
- What is a base oven cabinet?
- A base cabinet built with a bay for an under-counter wall oven. It is made in one width only — 30 inches, at $598.00 — so it fixes that much of your run before anything else is planned.
- What size cabinet does a 30-inch farmhouse sink need?
- The farm sink cabinet at this width displays for $806.00, but many sinks sold as 30 inches require a 33-inch cabinet because the apron needs bearing either side. The sink manufacturer's stated cabinet width is the one that governs.
Keep reading
The guides behind the numbers on this page.
- Kitchen dimensions to settle before buying cabinets
Appliance openings and the tolerances that have to be planned rather than found.
- Kitchen dimensions guide
Counter heights and depths, which decide whether an under-counter oven bay works.
- Wall and tall cabinet sizes
Where to look when the oven should be at eye level rather than under the counter.
- Types of base cabinets
The specialist boxes — oven, microwave, farm sink — set out against the ordinary ones.
- Kitchen layouts guide
Placing the cooking wall first, since this width fixes so much of it.
- Matching cabinets, countertops, backsplash and flooring
An apron sink changes the front of the run — worth reading before choosing one.