What problem this solves
The work triangle is the oldest ergonomic test in kitchen design, dating back to the 1940s research at the University of Illinois. It survives because it captures a real cost: every unnecessary step between the refrigerator, sink, and cooktop is wasted energy across thousands of meals a year. The NKBA formalised it in 2023 with tighter bands: each leg 1.2–2.7 m, total 3.6–7.0 m, no major traffic crossing the triangle. Most online calculators stop at the three numbers. Designers need to know whether the triangle they drew is actually usable — which means checking it against the island, the door swing, and the pantry zone.
Who it’s for
- Kitchen designers specifying layouts before millwork drawings
- Architects evaluating whether a renovation fits NKBA without a redesign
- General contractors checking a homeowner’s sketch before quoting
- Homeowners deciding between L and U before demoing a wall
Why NKBA numbers aren’t always gospel
NKBA guidelines assume one cook, average-height adults, and a kitchen used primarily for cooking. Modern kitchens aren’t always that: two-cook households, families with children in the kitchen, open-plan layouts where the cook is part of a social flow, and kitchens that double as homework stations all push the rules. The triangle also doesn’t capture storage, prep-zone adjacency, or appliance height — those need separate work-zone tests (the kitchen work-zone guidelines add a fourth zone, prep, and require 1.2 m clearance to any obstacle).
For wheelchair-accessible kitchens, ANSI A117.1 and ADA reduce all clearances and leg lengths by about 10%, and require a 1.5 m turning radius at one point in the kitchen. This calculator doesn’t enforce ADA — check local code separately.
Limitations
- Door-swing detection assumes a 90° arc; pivot doors and pocket doors are not modelled.
- Islands are treated as solid rectangles; an L-shaped island with a cutout is not handled.
- The triangle is calculated from a single point for each appliance. In reality the fridge reach is the handle (≈5 cm off the body), the sink reach is the centre of the bowl, and the cooktop reach is the centre of the burner zone.
- Single-cook vs multi-cook penalties aren’t applied — if two cooks regularly use the kitchen, the triangle should be wider.
- Floor plans with diagonal walls or angled corners aren’t rotated; coordinates assume an axis-aligned room.
Practical fixes for a failing triangle
Leg too long: the cooktop or fridge is too far from the sink. Move the sink first — it’s the one you touch 50+ times per meal. Leg too short: the cook is elbow-to-elbow with a helper; pull the refrigerator out 30–40 cm if the room allows. Traffic crossing: either route the main traffic lane around the triangle (best) or accept the compromise for an open-plan layout (common). Island collision: shorten the island by 20–30 cm or shift the cooktop off the wall by 20 cm to bring the triangle inside the gap.