Recessed Lighting Spacing and Layout
Layout is driven by illuminance, not by a fixed grid: work out the total lumens the room needs, divide by what each fixture produces, then arrange that many fixtures evenly.
From target illuminance to fixture count
Multiply the target illuminance in foot-candles by the room area in square feet to get the total lumens required. Divide by the lumens each fixture produces and round up.
Typical residential targets are modest. Kitchens, workshops and task areas need considerably more than a hallway or bedroom.
Arranging them
Spread the fixtures so the spacing is even in both directions and the distance from the wall is about half the spacing. That puts light on the walls instead of leaving dark edges.
A common rule of thumb is that the centre-to-centre spacing should not exceed half the ceiling height. Higher ceilings tolerate wider spacing.
Frequently asked
- What illuminance should I aim for?
- It depends on the room. Living spaces are commonly in the 10 to 20 foot-candle range, while kitchens and workspaces are set considerably higher.
- Does the calculator account for wall colour and daylight?
- No. It is a straightforward lumens-per-area estimate. Dark surfaces and no daylight mean you should aim higher.
- Is recessed lighting spacing a code requirement?
- No. It is a design calculation, not an electrical code rule. The electrical requirements concern the wiring and the fixtures, not the layout.
Related calculators
Educational information only — not professional engineering advice. Reference table values are pending review; see the methodology page.