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Will an island fit in my kitchen? Enter the room, the counter runs on each side and the aisle you want — this calculator subtracts the NKBA 42-inch work aisle from both sides and tells you the island slab that is left, or the aisles you would be standing in if you forced one anyway. Rooms in feet, everything else in inches.
Base cabinets are 24″ deep; enter 0 for a side that is a bare wall or a walkway. Measure to the counter edge, not the cabinet face — the overhang comes out of the aisle at both ends, and so does a standard-depth refrigerator standing proud of the run.
An island's true footprint is the slab plus 42 inches on every working side. A 72 × 39 island in the middle of a kitchen therefore commissions a 13 × 10 foot zone of floor all by itself, and that is the number that decides whether the room can have one.
| Island | Slab | Notes |
|---|---|---|
| Compact | 48 × 36″ | prep + one stool end |
| Standard | 60 × 36″ | the common builder island |
| Large | 72 × 39″ | sink or cooktop + 3 stools |
| Cart | 48 × 24″ | below this it has stopped being an island |
Depth is the number the room width has to supply, and it is only 36 or 39 inches. Everything else in the arithmetic is aisle. That ratio — three feet of island buying seven feet of clearance — is why kitchens fail in the aisles rather than the cabinets.
Add it up in one line: base cabinet, aisle, island, aisle, base cabinet.
| Arrangement | Adds up to | Room width |
|---|---|---|
| Both sides, 39″ island | 24 + 42 + 39 + 42 + 24 | 171″ — 14′-3″ |
| Both sides, 36″ island | 24 + 42 + 36 + 42 + 24 | 168″ — 14′-0″ |
| One side, walkway other | 24 + 42 + 39 + 36 | 141″ — 11′-9″ |
| Two cooks, both sides | 24 + 48 + 39 + 48 + 24 | 183″ — 15′-3″ |
Read the third row carefully, because it is the one that saves projects. Drop the far side from a work aisle to a plain walkway — no counter, nothing to open, just a route — and the kitchen a full island needs falls from fourteen feet three to eleven feet nine. Two and a half feet of room width, bought by admitting that nobody cooks on that side.
Take a kitchen a full twelve feet wide — 144 inches. Two facing runs of 24-inch base cabinets leave 96 inches between the counter faces. Drop a 72 × 39 island in the middle and 57 inches of floor is left, split into two aisles of 28½.
The island does not fit, and the kitchen is twelve feet wide. That is the whole reason this calculator exists, and it is why the verdict panel reports the forced aisles rather than just saying no: the number you want when the answer is no is by how much.
The honest moves from there, in order: a peninsula off one run, which needs an aisle on one side instead of two; a cart you can push out of the way; or dropping one side to a walkway and taking the 11′-9″ arrangement. What does not work is shaving the aisle, because the aisle is the part somebody has to stand in with a drawer open.
| Appliance | W × D | Notes |
|---|---|---|
| Refrigerator | 36 × 33″ | standard-depth — it WILL stand proud of 24″ cabinets |
| Counter-depth | 36 × 27″ | sits nearly flush; trades ~20% capacity for the look |
| Range | 30 × 26″ | pro ranges run 36–48″ wide |
| Wall oven | 30 × 24″ | door drops into the aisle |
| Dishwasher | 24 × 24″ | 30″ of standing room in front; 18″ compact exists |
"Counter-depth" is the most misunderstood word in appliance shopping. It means the box is about 24–27″ deep so the front face lands even with the counters — doors and handles still stand a few inches proud. A standard 33″-deep fridge in a 24″ cabinet run projects most of a foot into the walkway, and if that fridge faces your island, it is the fridge and not the cabinet that sets the aisle.
Depth is published three different ways — the box alone, the box plus the door, or the box plus door plus handle — and a listing rarely says which. A "33-inch" standard-depth fridge can measure 36 to the front of its handle, and that difference is a third of your walkway. Every figure here is a planning size; the installation sheet for the model you are buying is the authority, and it is free.
The 42-inch work aisle, the 48 for two cooks, the 36-inch counter height and the 42-inch bar are NKBA Kitchen Planning Guidelines — a published industry standard, not a design opinion, and the strongest source set in anything we publish. The island slabs and appliance footprints are the research-verified figures in Poché's own furniture library. Full write-up: kitchen clearances & island sizes.
What the arithmetic cannot see is your plan: which way the fridge door swings, whether the range and the dishwasher face each other across the aisle, and where the doorway into the room lands. Those decide the kitchen. The width just decides whether there is a conversation to have.
About 14 feet with cabinets on both sides: 24″ of base cabinet, a 42″ aisle, a 39″ island, another 42″ aisle and another 24″ of cabinet is 171″, or 14 feet 3. A 36″ island brings that to exactly 14 feet. With cabinets on one side only and a walkway on the other, 11 feet 9 does it. A 12-foot-wide kitchen cannot take a full island, which surprises almost everybody.
42″ of work aisle, and 48 where two people cook. That is the NKBA figure and it is not generosity — it is an open dishwasher door plus a human, measured counter-edge to counter-edge rather than cabinet to cabinet. A walkway that is not a work zone can drop to 36. Below 36 you are into the range where two people cannot pass and one person cannot open a lower cabinet while standing there.
Anything under about 48 × 24″ has stopped being an island and started being a cart. The three slab sizes worth planning around are 48 × 36 for prep with one stool end, 60 × 36 as the common builder island, and 72 × 39 where a sink or cooktop and three stools have to live on it. Remember the slab is not the footprint: an island's true footprint is the slab plus 42″ on every working side.
No, and the arithmetic is worth seeing. Twelve feet is 144″. Two facing runs of 24″ base cabinets leave 96″ between the counter faces. Drop a 72 × 39 island in the middle and 57″ of floor is left, split into two aisles of 28½. Both are under the 42″ work aisle. Both are under the 36″ walkway. A dishwasher door alone drops about 24″ into one of them. The honest move in that room is a peninsula off one run, or a cart you can move.
Its length is limited by the room's other dimension, because the 42″ clearance applies to every working side including the ends. A 72″ island in a room 13 feet long uses 72 of the 156″ and leaves 42 at each end exactly. Shorten the room to 12 feet and the same island leaves 36 at each end, which is walkway width rather than work-aisle width. Stool seating is a separate width problem: each stool wants 21–24″ of run and about 15″ of knee space under the overhang.
Counter edge to counter edge, not cabinet face to cabinet face. Countertops overhang their base boxes and that overhang comes out of the aisle at both ends, so an aisle measured to the cabinets is optimistic by more than people expect. Appliance fronts count too: a standard-depth refrigerator in a 24″ cabinet run projects most of a foot into the walkway, and its door and handle add more.
The demo plan is public and needs no account. Drop an island stencil on a real drawing at true scale, watch the 42-inch halo draw itself, and see the aisle pinch the moment the slab grows.
Open the demo plan →