In our sample run, an island with a 33 in sink base and a 24 in dishwasher takes 75 in of cabinets: NKBA asks for 24 in of counter on one side of the sink and 18 in on the other, and the dishwasher can sit under the 24 in side. That is cabinet arithmetic, not an order size: end panels and overhangs make the top longer, and the sink’s cutout and minimum cabinet and your countertop maker’s support rules come first. With counter stools on the far side it is 40½ in deep. The smallest sink-island plans we drew that pass our planner’s checks are 12 × 13 ft for one wall plus the island, with one side open, and for an L, 13 × 13 ft with one side open or 16 × 14 ft closed.
How big an island with a sink needs to be
NKBA’s kitchen planning guidelines ask for counter beside the main sink: 24 in on one side and 18 in on the other, and the dishwasher within 36 in of the sink. The dishwasher goes under the counter, so its top counts as part of the 24 in:
Before you order, check the sink’s spec sheet for its cutout and minimum base cabinet: Kraus’s 30 in KHU100-30, for one, asks for a 33 in base and comes with cutout templates. Then check your countertop maker’s rules for the cutout: Cambria asks for support within 3 in of any cutout, and MSI recommends supporting a sink independently of its quartz top. End panels and any overhang at the ends make the top longer than the cabinets.
Depth is the same as for any island: 25½ in for one row of base cabinets under a counter, or 40½ in with counter-height stools: 24 in cabinets, a 1½ in lip and 15 in of knee space (NKBA). Each stool takes 24 in of length, so a 75 in island seats three on its far side. Island sizes and the room they need are on kitchen island dimensions.
Around it, keep a 42 in work aisle on the side where the cook stands, 48 in if two people cook, and 36 to 44 in behind the stools (NKBA). See space between island and counter.
Plans with the sink in the island
Every plan below was drawn by our kitchen layout planner with a 36 in fridge, a 33 in sink base, a 24 in dishwasher and a 30 in range, and checked against NKBA’s aisles, landing areas and work triangle.
- Narrowest aisle: 42 in
- Behind the stools: 36 in
- Work triangle: 16 ft 6 in
- Counter: 12 ft 6 in
One wall plus a sink island: 12 × 13 ft
The wall keeps the fridge and the range with counter between them; the island takes the sink, the dishwasher and two stools. Across the room: 25½ in of counter, a 42 in aisle, the 40½ in island and 36 in behind the stools.
- Works: passes every check our planner counts; the sink has 24 in of counter over the dishwasher and 36 in on the other side.
- Watch: 36 in behind the stools is room to edge past them, not to walk past; that takes 44 in.
- Narrowest aisle: 42 in
- Work triangle: 14 ft 11 in
- Counter: 13 ft 9 in
One wall plus a sink island: 14 × 13 ft
Two more feet along the wall make room for an 8 ft island and a third stool. The fridge, the range and 13 ft 9 in of counter in all; the island stands 42 in from the fridge door.
- Narrowest aisle: 42 in
- Behind the stools: 38¼ in
- Work triangle: 12 ft 11 in
- Counter: 20 ft 6 in
L-shaped plus a sink island: 13 × 13 ft, one side open
With the room open on one side, the stools can face out and the island fits in a 13 ft square. The L keeps a 42 in aisle to the island on both legs, and the triangle is tight: 12 ft 11 in.
- Works: 20 ft 6 in of counter, well past NKBA’s 158 in target.
- Watch: 38¼ in behind the stools, enough to edge past.
- Narrowest aisle: 42 in
- Behind the stools: 50¼ in
- Work triangle: 13 ft 1 in
- Counter: 21 ft 1 in
L-shaped plus a sink island: 16 × 14 ft, closed
With walls on all four sides, the stools need their own clearance to a wall, so the room grows to 16 ft across. Everyone can walk behind the stools (50¼ in), and the island is 84 in long.
- Narrowest aisle: 42 in
- Behind the stools: 50¼ in
- Work triangle: 14 ft 1 in
- Counter: 19 ft 1 in
- 1 NKBA check short
One foot less: 15 × 14 ft is short
Take a foot off the room and the island drops to 72 in, under the 75 in this sink base and dishwasher need with NKBA’s counter beside the sink. The sink keeps 36 in on one side but only 3 in on the other, where NKBA asks for 18 in.
A prep sink in the island
A second, smaller sink for washing vegetables or filling pots needs much less island. NKBA asks for 3 in of counter on one side of a second sink and 18 in on the other. Six maker spec sheets for bar and prep sinks 13¾ to 15⅛ in wide (two from Kraus, and one each from Elkay, Kohler, Blanco and Ruvati) call for an 18 in base cabinet, so the shortest run that holds one is:
A 17 in prep sink needs a 21 in base (Kraus KHU101-17), and a 23 in workstation sink at least a 24 in base (Kohler Prolific). Stock lines differ: Hampton Bay’s sink bases start at 30 in, while Wellborn lists 18 in, 21 in and 24 in ones. A prep sink still needs a drain, a vent and water, the same as a full sink.
A sink in a peninsula instead
A peninsula is attached at one end, so it needs no aisle around that end, and a sink fits in a smaller room. In our plans an L with the sink in a 90 in peninsula and two stools passes in 13 × 13 ft with a door, where an island needs 16 × 14 ft. The plan is on kitchen peninsula, and a G-shaped kitchen with the sink in its peninsula is in G-shaped kitchens.
The dishwasher in the island
- Next to the sink: within 36 in of it, edge to edge (NKBA). In every plan above it sits right beside the sink base.
- Standing room: at least 21 in between the dishwasher and any counter at a right angle to it (NKBA). On an island that’s easy: nothing turns a corner.
- The door: it opens into the work aisle, which is why the aisle on the sink side should be the full 42 in. A standard dishwasher needs an opening 24 in wide and 24 in deep under the counter: see dishwasher dimensions.
Seating across from the sink
Stools on the far side face the person at the sink, which is the point for many people: you can talk while you wash up. Water splashes travel, though. Keep the sink well back from the seating edge: on a 40½ in island the sink base sits in the 24 in cabinet row and the stools have the 15 in overhang. A raised bar on the seating side (a 42 in counter with 12 in of knee space, NKBA) hides the sink from the seats. Stool spacing and seats at the ends are covered in kitchen island seating.
Plumbing and power
A sink in the island needs a drain, a vent and water lines brought up through the floor, and an island has no wall for the vent pipe that a wall sink uses. Which arrangement is allowed depends on your plumbing code, so plan the island’s position with a licensed plumber before ordering cabinets, and ask the building department about permits. Moving the sink costs more than keeping it where the pipes already are.
Island outlets depend on the code your area has adopted. The 2020 National Electrical Code asks for at least one outlet for the first 9 sq ft of island counter and one more for each 18 sq ft; the 2023 edition no longer requires one but asks for a way to add it later. A licensed electrician and your local code decide.
Sink or cooktop in the island?
- Sink: the most-used spot faces the room; dishes stay on the island, away from the stove. Needs water, a drain and a vent.
- Cooktop: NKBA asks for 9 in of counter behind it and the same 12 and 15 in beside it as on a wall; it needs gas or power, and an island hood or a downdraft for the steam and smoke. See kitchen island with a stove.
- Neither: a prep and seating island needs no utilities beyond outlets, and is the easiest to change later.
Questions people ask
How big does a kitchen island with a sink need to be?
In our sample run, 75 in of cabinets for a 33 in sink base and a 24 in dishwasher with NKBA’s 24 and 18 in of counter beside the sink, 25½ in deep, or 40½ in with counter-height stools. The sink’s cutout and minimum cabinet, end panels and the countertop maker’s support rules set the final size.
Can you put a dishwasher in a kitchen island?
Yes, beside the sink base. NKBA asks for it within 36 in of the sink and 21 in of standing room beside it, which an island gives easily.
What is the minimum room size for an island with a sink?
In our plans, 12 × 13 ft for one wall plus a sink island with one side open, 13 × 13 ft for an L open on one side, and 16 × 14 ft for an L in a closed room.
Is a sink in the island a good idea?
It is if you want to face the room while you clean up and have the floor space. The drawbacks: a longer island, plumbing under the floor, and splashes on the seating side.
Final Takeaway
Plan on about 75 in of island for a 33 in sink base and a 24 in dishwasher with NKBA’s counter on both sides, then let the sink’s spec sheet and your countertop maker settle the cutout, the supports and the final top. The smallest rooms in our plans are 12 × 13 ft with one side open, or 16 × 14 ft for an L in a closed room. The drain, vent, water and outlets follow your local codes, so involve a licensed plumber and electrician before you order cabinets.
Main Sources
- NKBA’s free Kitchen Planning Guidelines with Access Standards: work aisles (42 in for one cook, 48 in for two), walkways (36 in), the work triangle (each leg 4 to 9 ft, 26 ft in all), landing areas beside the sink, cooktop and fridge, the dishwasher’s place and standing room, and seating clearances. This is the older free edition; the paid 5th edition (June 2026) may change some numbers. The second (prep) sink and the dishwasher rules are in the same guidelines.
- National Electrical Code island outlet rules, as summarized by Leviton for the 2020 NEC and the 2023 NEC, and by Larimer County, Colorado, 2023 NEC significant code changes
- Bar and prep sink spec sheets, each with its minimum base cabinet: Kraus KHU15 and KBU17, Elkay BLR15, Kohler K-5287, Blanco Precis Bar and Ruvati RVH8304 (18 in); Kraus KHU101-17 (21 in); Kohler K-23650 (24 in)
- Sink base widths: American Woodmark Hampton Bay spec guide (January 2025) and the Wellborn Select spec catalog 2024–2025
- Wolf Classic Cabinetry product specifications: base cabinets 34½ in high and 24 in deep, stock widths 9 in and 12 to 42 in in 3 in steps (45 and 48 in by special order), wall cabinets 12 in deep
- Caesarstone: the standard depth of kitchen countertops, 25½ in (24 in cabinets plus a 1½ in overhang)
- Kraus spec sheets: a 30 × 18 in sink needs a 33 in base, a 33 × 22 in double sink a 36 in base
- Bosch 300 Series SHS3ADF5N spec sheet: a 24 in wide, 24 in deep, 33⅞ to 35 in high opening
- Samsung “Will it fit” sheets for a counter-depth (28¾ in to the door front) and a standard-depth fridge (34¼ in to the door front); the planner adds 1 in behind, as KitchenAid’s guide asks
- Whirlpool WFES3530R 30 in range dimension guide: 29⅞ in wide, 25 7/16 in deep without the handle
- Kraus KHU100-30 spec sheet: a 33 in minimum base cabinet and cutout templates; Cambria, countertop installation technical guideline (version 23A-0220): support within 3 in of any cutout; MSI, Q Quartz installation guidelines: sinks supported independently of the top
Checked 19 and 20 October 2026; the Kraus, Cambria and MSI sink and cutout notes checked 28 October 2026. The plans are drawn and measured by our planner; room sizes are wall to wall, width first.