How to use the kitchen work triangle checker
The work triangle is the oldest and best-known rule of kitchen planning. It links the three places a cook moves between most often (the sink, the cooktop and the refrigerator) and asks that they be close enough to save steps but far enough apart to leave counter space and room to move. It's a quick way to test a layout on plan before it goes any further.
- Measure the three legs on your plan, from the centre front of the sink, the centre of the cooktop or range, and the centre of the refrigerator. Use straight lines, in feet or metres.
- Answer the two layout questions: whether an island or peninsula blocks any leg by more than 12 inches, and whether a main traffic route passes through the triangle.
- Read the results: each leg and the perimeter are checked against the guideline, the corner angles are calculated and the triangle is drawn to scale so you can see its shape.
Work triangle rules and formulas
Each leg: 4 ft ≤ leg ≤ 9 ft (1.22 m to 2.74 m)
Perimeter P = a + b + c, 13 ft ≤ P ≤ 26 ft (3.96 m to 7.92 m)
Valid triangle: each leg < sum of the other two
Angle at sink = acos((a² + c² − b²) ÷ 2ac)
Here a is sink to cooktop, b is cooktop to fridge and c is fridge to sink. The leg and perimeter limits follow the NKBA Kitchen Planning Guidelines; the 13 ft minimum perimeter is a widely used design rule rather than a code. If one leg is longer than the other two combined, the three points can't form a triangle and one of your measurements is wrong. A very flat triangle, with one angle well over 120°, usually means the work points are strung along a single wall.
| Layout | Typical legs | Typical perimeter | Watch out for |
|---|---|---|---|
| Galley | 4–7 ft | 14–20 ft | Through traffic down the aisle |
| L-shaped | 5–9 ft | 16–24 ft | Long leg to the fridge at the end of a run |
| U-shaped | 5–8 ft | 15–22 ft | Corner storage between work points |
| Island | 5–9 ft | 16–26 ft | Island blocking a leg |
| Single wall | 3–6 ft | Very flat triangle | Too little counter between appliances |
Worked examples
A compact galley
Sink to cooktop 6 ft, cooktop to fridge 7 ft, fridge to sink 5 ft. Every leg is between 4 and 9 ft and the perimeter is 18 ft, comfortably inside 13 to 26 ft. The angles are about 78° at the sink, 44° at the cooktop and 57° at the fridge, a well-balanced triangle.
A large island kitchen
The sink is on the island, the range on the back wall 10 ft away, the fridge 8 ft from the range and 12 ft from the sink. Two legs are over 9 ft and the perimeter is 30 ft, past the 26 ft limit. Moving the fridge to the end of the island run, about 7 ft from the sink, brings the legs to 10, 8 and 7 ft. The perimeter is now 25 ft, but the sink-to-cooktop leg is still too long, so the next move is to shift the sink along the island toward the range.
A metric L-shaped kitchen
Sink to hob 1.5 m, hob to fridge 2.4 m, fridge to sink 2.1 m. All three legs fall between 1.22 and 2.74 m and the perimeter is 6.0 m (19.7 ft), well within the 3.96 to 7.92 m range. Provided the route to the garden door runs past the fridge end rather than between sink and hob, this layout passes.
Who this checker helps
- Architects testing kitchen options in early plans and checking that a moved wall or new island still works.
- Kitchen and interior designers explaining layout choices to clients with clear numbers.
- Cabinet makers and kitchen showrooms reviewing customer sketches before detailed design.
- Contractors checking that relocated plumbing and gas points keep a workable layout.
- Homeowners planning a remodel and comparing layouts.
- Students learning residential planning standards.
Practical tips
- Leave landing space: at least 24 in (600 mm) of counter beside the sink, 15 in (380 mm) beside the fridge handle side and 12 to 15 in (300 to 380 mm) either side of the cooktop.
- Check aisle widths too. The furniture clearance guide covers kitchen aisles, island clearances and dining space.
- Get the kitchen's floor area for budgets and finishes with the square footage calculator, then price the floor with the tile calculator.
- Keep the fridge at the outside of the triangle so family members can reach it without entering the cooking zone.
- For two cooks, draw two triangles that share at most one leg, typically with a prep sink on the island.
Once the layout works on plan, turn a quick sketch of the kitchen into a photoreal image with Sketch to Render.
