Kitchen island size and clearance calculator
Plan a kitchen island around NKBA clearances: 42 inches of aisle for one cook (48 for two), 24 inches of width per stool, and a 15-inch overhang at counter height. An island for four stools needs about 96 inches of length. A 15 by 16 foot kitchen fits an island about 10 feet long.
Updated · By the Interior Redesign AI editorial team · Sources cited on the page
We subtract the perimeter counters, a work aisle on the work side and the larger of the aisle and the seating clearance on the seating side, then a 36 in walkway at each end (NKBA Guidelines 6-9). Measure wall to wall, ignoring baseboards.
Largest island that fits
120 in × 39 in
Seats 5 at 24 in each. Depth shown is a 24 in base plus overhang; up to 46 in is available.
| Max island length | 120 in |
|---|---|
| Max island depth | 46 in |
| Depth needed (24 in base + overhang) | 39 in |
| Seating overhang (knee space) | 15 in |
| Stools at 24 in each | 5 |
| Work aisle | 42 in |
| Seating-side clearance | 42 in |
| End walkways | 36 in each |
- OKDepth: 46 in available, 39 in needed
- OKLength: 120 in available, 36 in is a practical minimum
NKBA planning guidelines, not code. Appliance doors and dishwashers opening into an aisle can need more room; check door swings.
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Key numbers
- Work aisle around the island
- 42 in (one cook), 48 in (two or more) (NKBA Guideline 6)
- Walkway
- 36 in minimum (Guideline 7)
- Width per seat
- 24 in (Guideline 9)
- Knee space / overhang
- 18 in at 30 in high, 15 in at 36 in, 12 in at 42 in
- Behind seated diners
- 32 in with no traffic, 36 in to edge past, 44 in to walk past (Guideline 8)
- Accessible kitchen
- 60 in for wheelchair passage behind seats and between opposing counters
- Island for 4 stools
- 96 in (8 ft) of seating length
Worked example
A 16 x 15 ft kitchen with counters on both long walls
Room 16 ft (192 in) long and 15 ft (180 in) wide, 25 in deep perimeter counters on two walls, one cook, counter-height seating with people edging past.
- Depth: 180 − 2 × 25 (counters) − 42 (work aisle) − 42 (seating side, the larger of 42 and 36) = 46 in available.
- Needed: 24 in base + 15 in overhang = 39 in, so it fits.
- Length: 192 − 2 × 36 (walkways) = 120 in.
- Seats: 120 ÷ 24 = 5 stools.
An island up to 120 × 39 in fits, seating 5.
How we calculate
Across the room we subtract the perimeter counters on one or two walls, the work aisle on the work side, and on the seating side the larger of the work aisle and the seating clearance you pick. What is left is the deepest island that fits. Along the room we subtract a 36 in walkway at each end (42 in in the accessible mode).
The island depth you need is a 24 in base cabinet plus a seating overhang equal to NKBA's knee-space depth for the counter height: 18, 15 or 12 inches. Stools are 24 inches each, so the stool count is the island length divided by 24, rounded down.
These are NKBA planning guidelines, not code, and the model assumes counters along the long walls with open ends. Appliance doors, a dishwasher opening into the aisle, or a column change the answer, so check them on your plan.
Estimates, sources
Planning estimates and published guidelines, not quotes, designs or code rulings. Local prices, your home and your jurisdiction's adopted code decide the real answer: get local bids and check with your inspector.
- Kitchen Planning Guidelines with Access Standards (National Kitchen & Bath Association (NKBA), 2015): work triangle 26 ft max, legs 4-9 ft; aisles 42 in (one cook) / 48 in (two); walkways 36 in; seating clearance 32/36/44 in; knee space 24 in wide; landing areas; 150 cfm ventilation; storage frontage
Island length for 2, 3, 4 or 5 stools
Give each seat 24 inches of counter length, per NKBA. End seats work, but they need the clearance behind them too.
| Stools | Seating length | Overhang at counter height (36 in) |
|---|---|---|
| 2 | 48 in (4 ft) | 15 in |
| 3 | 72 in (6 ft) | 15 in |
| 4 | 96 in (8 ft) | 15 in |
| 5 | 120 in (10 ft) | 15 in |
Overhang by counter height
The lower the counter, the deeper the knee space you need. Table height (30 in) needs 18 inches, counter height (36 in) needs 15 inches and bar height (42 in) needs 12 inches. Longer overhangs usually need supports or brackets; ask your fabricator about stone.
| Counter height | Width per seat | Knee-space depth |
|---|---|---|
| 30 in (table) | 24 in | 18 in |
| 36 in (counter) | 24 in | 15 in |
| 42 in (bar) | 24 in | 12 in |
How to use this tool
Measure the room
Wall to wall, along the island and across it.
Set counters and cooks
Perimeter counter depth, which walls have counters, one or two cooks.
Add seating
Counter height and whether people walk behind the stools.
Read the fit
Max island length and depth, stool count and each clearance.
Questions
How much space do you need around a kitchen island?
NKBA recommends work aisles of at least 42 inches for one cook and 48 inches for two or more, and walkways of at least 36 inches. In an accessible kitchen, plan 60 inches.
What size island fits 4 stools?
At 24 inches per seat, four stools need 96 inches (8 feet) of seating length. Add the overhang to the island's depth: 15 inches at counter height.
How much overhang does a kitchen island need for seating?
NKBA's knee-space depth is 18 inches at a 30 inch table height, 15 inches at a 36 inch counter and 12 inches at a 42 inch bar.
How much room do you need behind island stools?
32 inches from the counter edge if nobody passes behind, 36 inches for people to edge past, and 44 inches for people to walk past, per NKBA Guideline 8.
What is the minimum kitchen size for an island?
With 25 inch counters on both walls, a 42 inch aisle each side and a 24 inch deep island, you need about 158 inches (13 feet) wall to wall, and more for seating.
Is this a building code?
No. These are NKBA planning guidelines. Codes rarely set island clearances, but appliance doors, egress and local rules can. Check your plan with your designer or contractor.
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