What is the minimum room size for a kitchen island?

With cabinets on one wall, a 900 mm deep island and a 1000 mm work aisle each side, the room needs to be at least 600 + 1000 + 900 + 1000 = 3500 mm deep. With cabinets on both facing walls it is 4100 mm. Along the island's length, allow 900 mm to walk past each end, so a 1200 mm island wants a room at least 3000 mm wide. Below that, a peninsula gives you the same worktop with one aisle instead of two.

How much overhang does island seating need?

About 300 mm (12 inches) of overhang at a 900 mm worktop for knees, 380 mm (15 inches) for comfort, and 600 mm (24 inches) of width per seat. Behind the seats, leave 800 mm to a wall if nobody walks past, and 1100 mm if the route through the kitchen runs behind the diners.

Can I put the sink or hob on the island?

Yes, and both need services through the floor: water and waste for a sink, and for a hob either a ducted ceiling hood or a downdraft extractor with somewhere to vent. A hob on an island also needs landing space on both sides and a hood above, and the planner's hob checks apply to it just as they do on a wall. Budget for the floor to be opened.

Does the planner check island clearances?

Yes. The island is a free-standing unit you drag anywhere. The walkway check measures the gap to every facing run and warns below 1000 mm and flags below 900 mm; door swings, loading space and the work triangle are checked across it like any other unit.

Kitchen Island Clearance: Space Around an Island (mm & in)

Realistic render of an L-shaped kitchen with a 1200 by 900 mm island in the middle of a 4800 by 4200 mm room, graphite handleless cabinets and a white quartz worktop — The island starter layout rendered from the planner: a 1200 × 900 mm island in a 4800 × 4200 mm room, with 1000 mm or more on every side.

The aisles around an island

Measure from the edge of the island worktop to the edge of the facing worktop, not cabinet to cabinet. A side where somebody works needs a work aisle; a side that is only walked along needs a walkway; a side with stools needs room for the stools and for anyone passing behind them.

Clearances around an island
Side of the island	Millimetres	Inches	Kind
Working side, one cook	1000–1070	42	Guideline
Working side, two cooks	1200	48	Guideline
Walkway only	900	36	Guideline
Behind seating, no traffic	800	32	Guideline
Behind seating, people walk past	1100	44	Guideline
Planner warning / conflict	1000 / 900	39 / 35	Default

An island's dishwasher or oven door opens into the aisle: add its door depth if it faces another opening door across the aisle.

Seating

Each seat wants about 600 mm (24 inches) of width along the worktop. At a 900 mm worktop height the overhang for knees is 300 mm at a minimum and 380 mm to sit comfortably; at a raised 1050 mm bar it is 300 mm; at a 750 mm table height it is 450 mm. An overhang past 300 mm in stone needs support brackets or a thicker slab, which your fabricator specifies.

How big an island should be

A useful island is at least 600 mm deep and 1200 mm long, which is one cabinet and a landing surface. The planner's default island is 1200 × 900 mm: 900 deep gives a 600 mm cabinet plus a 300 mm seating overhang on the other side. Islands over 1200 mm deep become hard to reach across and to clean; islands over 2400 mm long become a wall you walk around.

The smallest room that takes one

Add the pieces across the room, wall face to wall face:

Minimum room depth for an island
Layout across the room	Sum	Minimum depth
Wall run + aisle + island + walkway + wall	600 + 1000 + 900 + 900	3400 mm (11' 2")
Wall run + aisle + island + aisle (both sides worked)	600 + 1000 + 900 + 1000	3500 mm (11' 6")
Wall run + aisle + island + aisle + wall run	600 + 1000 + 900 + 1000 + 600	4100 mm (13' 5")
Along the island: walkway + island + walkway	900 + 1200 + 900	3000 mm (9' 10") wide

A room narrower than that is not a failure; it is a peninsula. Attach the same 1200 × 900 worktop to the end of a run and you keep the seating and the extra surface with one aisle instead of two. The planner's small kitchens page works through the sizes.

Sink and hob on an island

Anything wet or hot on an island brings services up through the floor. A sink needs supply and waste, and the waste needs a fall to the drain, which decides whether the floor can be opened. A hob needs extraction: a ceiling hood, ducted, or a downdraft unit with somewhere to vent, and the same landing space beside it as on a wall. Sockets on an island are governed by local electrical rules, which in the US changed in the 2023 code cycle; ask before assuming. The layout checks treat an island hob and sink exactly as they treat wall ones.

A worked example

The planner's island starter is a 4800 × 4200 mm room with an L of cabinets on the back and left walls and a 1200 × 900 island standing at 1850 mm from the left wall and 2000 mm from the back wall, its fronts facing the door.

Clearances in the island starter layout
Gap	Calculation	Result
Island to back-wall run	2000 − 600 worktop depth	1400 mm, two-cook aisle
Island to left-wall run	1850 − 600	1250 mm, two-cook aisle
Island to right wall	4800 − 1850 − 1200	1750 mm walkway and door route
Island to front wall	4200 − 2000 − 900	1300 mm, room for stools and passing

Measured from the island's edge to the facing worktop edge or wall face. Open the layout in the planner and shrink the room to see the walkway check appear.

Questions

How this page was made

Guideline figures are from the NKBA Kitchen Planning Guidelines, converted from inches and rounded to the nearest 10 mm. The worked example is the planner's island starter layout, measured from its saved dimensions; the render above is unedited planner output from 18 September 2026. Seating overhang and stone support figures are typical fabricator practice, not a standard: confirm with the worktop supplier.

Sources

NKBA Kitchen Planning Guidelines · work aisle, walkway and seating clearance figures, quoted in inches
Setout Kitchen island starter layout · the 4800 × 4200 mm example the worked figures come from

Written by the person who builds the planner, who is not a kitchen designer or an electrician: the guides say where a professional or a local code decides. Found a mistake? Write to us and it will be corrected with a note on this page.

Keep reading

Try it on your room

Enter your measurements, start from a layout and let the layout checks find what will not fit. Planning is free for 1 month, and the dimensioned plan is yours to download.

Start designing free