Calculators
Kitchen island fit checker
An island is the only piece of kitchen furniture that takes space from two aisles at once, which is why the arithmetic catches people out.
On this page (3 sections)
Short answer
A work aisle wants 42 in (107 cm) for one cook and 48 in (122 cm) for two or where people pass through. A seating side needs 44 in (112 cm) so someone can walk behind an occupied stool. Below 36 in (91 cm) an aisle stops working as soon as a dishwasher door opens.
The numbers, at a glance
- Work aisle, one cook
- 42 in (107 cm)
- Work aisle, two cooks
- 48 in (122 cm)
- Behind seated stools
- 44 in (112 cm)
- Knee overhang at 36 in counter
- 12 in (30 cm)
Kitchen island fit checker#
Checks an island against the aisle widths in the NKBA planning guidelines and tells you the largest island the room can take.
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How it decides#
The checker lays the room out across its narrow direction as a strip:
counter run + aisle + island + aisle + counter run = room width
then compares each resulting aisle against the NKBA figure for the way you use the kitchen. If you tell it there is seating, the seated side is checked against 44 in (112 cm) rather than the work-aisle figure, because the stool occupant's body is already using the first 20 in (51 cm) of that aisle.
It also checks the ends. An island that leaves less than 36 in (91 cm) at each end turns the ends into dead corners, and a fridge or oven door swinging into one of them makes it worse.
Why 42 inches and not 36#
Thirty-six inches is a walkway: a body plus a margin. A work aisle has to accommodate a person bending into a base cabinet, a dishwasher door projecting 24 in (61 cm), an oven door at 21 to 24 in, and someone else getting past. Open a dishwasher in a 36 in aisle and the remaining gap is 12 in (30 cm), which is not a gap.
At 42 in, an open dishwasher leaves 18 in (46 cm), which is a squeeze but passable. At 48 in it leaves 24 in (61 cm), which is why two-cook kitchens use that figure.
The alternatives when it does not fit#
- Peninsula. Attached at one end, so it only needs one aisle. Buys back 42 in of room width instantly.
- Rolling table or butcher's block. 24 x 36 in (61 x 91 cm), parked against a run and pulled out to work.
- Shallow island at 30 in (76 cm) deep. Still takes a stool on one side, still gives a full run of worktop.
- Extended worktop over a base run with a 12 in overhang for two stools, which delivers most of the social function of an island for none of the floor.
The full island clearances guide works through the door-swing conflicts and seating dimensions in more detail.
Frequently asked questions#
What should I enter for counter depth?
Enter the finished depth from the wall to the front edge of the worktop, which is normally 25 in (64 cm) for a 24 in (61 cm) base cabinet plus the overhang. Enter 0 for a side with no run at all. If a wall has tall pantry units rather than base cabinets, enter their depth instead, usually 25 to 27 in (64 to 69 cm).
What is the minimum room width for an island?
Add it up: 25 in (64 cm) of counter run, 42 in of aisle, 40 in (102 cm) of island and 36 in (91 cm) on the far side comes to 143 in, about 12 ft (3.7 m). With runs on both sides and 42 in aisles you need about 14 ft (4.3 m).
How big should a kitchen island be?
Rarely smaller than 40 x 60 in (102 x 152 cm), or it does not earn its floor space. 40 x 84 in (102 x 213 cm) is a common working size. Depth beyond about 48 in (122 cm) starts to put the middle out of reach from either side.
How much overhang do island stools need?
12 in (30 cm) of knee overhang at a 36 in counter-height top, 15 in (38 cm) at a 30 in table-height top, and 10 in (25 cm) at a 42 in bar. Allow 24 in (61 cm) of width per stool, and support any overhang beyond 12 in with brackets or a corbel.
Sources and standards referenced#
- Kitchen and Bath Planning Guidelines with Access Standards NKBA, 2022 editionWork aisle, walkway and seating clearance guidelines
- 2021 International Residential Code International Code CouncilGeneral means of egress and clear width requirements
We cite published codes, industry planning guidelines and manufacturer specifications. Where a figure is our own recommendation rather than a published standard, the text says so. See how we measure.