Equal spacing· 3 min read
How to Space Recessed Lights: Spacing and Distance From the Wall
How to space recessed spotlights evenly in a 4 × 3 m room: centre-to-centre spacing, distance from the wall as half the spacing, and marking positions.
Recessed spotlights are drilled once, and a hole in the wrong place is hard to fix. The two most common problems: lights too close to a wall, throwing sharp cones of light onto it, and an outer row too far from the wall, leaving the edges of the room dark. A simple rule and an exact calculation avoid both.
The rule: half the spacing to the wall
Lighting manufacturer ERCO recommends, for downlights, a distance to the wall of half the luminaire spacing. As a rough guide, it says the spacing between two downlights may be up to 1.5 times the height of the luminaire above the working plane. Corner luminaires should sit on the 45° line of the corner.
Half the spacing at the wall makes sense: the room is split into equal squares or rectangles with each light in the middle of its own. The walls then get the same light as the middle of the room. In the calculator this is the “Half a gap” end option.
Example: a 4,000 × 3,000 mm room
The ceiling is 2,600 mm high (about 8.5 ft) and the working plane (a table) is, say, 850 mm. The luminaire is therefore 1,750 mm above the working plane, and ERCO's rough upper limit for spacing is 1.5 × 1,750 = 2,625 mm. For more even light we use a stricter limit of 1,200 mm centre to centre. The cut-out of the light in the example is 70 mm.
| Direction | Max centre to centre | Lights | Actual spacing | Light centre from wall |
|---|---|---|---|---|
| 4,000 mm | 1,200 mm | 4 | 1,000 mm | 500 mm |
| 3,000 mm | 1,200 mm | 3 | 1,000 mm | 500 mm |
| 4,000 mm | 2,625 mm | 2 | 2,000 mm | 1,000 mm |
| 3,000 mm | 2,625 mm | 2 | 1,500 mm | 750 mm |
With a 1,200 mm limit you get a 4 × 3 grid — 12 lights on a 1,000 × 1,000 mm grid, 500 mm from each wall. The corner light is 500 mm from both walls, so it sits exactly on the corner diagonal. At the 2,625 mm upper limit, 2 × 2 = 4 lights would do, but the room would be lit less evenly.
Marking positions
- Along 4,000 mm: light centres at 500, 1,500, 2,500 and 3,500 mm from the wall.
- Along 3,000 mm: centres at 500, 1,500 and 2,500 mm from the wall.
- Draw these lines on the ceiling in both directions — the lights go where they cross.
The calculator works one direction at a time. Run the length and the width of the room with the same limit. If each direction gives a different spacing, that's fine — what matters is that “half the spacing to the wall” holds in each direction.
Equal spacingOpen this example in the spacing calculatorA narrow hallway
A hallway 1,200 mm wide and 5,000 mm long with the same 1,200 mm limit: across, you get one light in the middle (600 mm from the wall); along, 5 lights 1,000 mm apart, the first 500 mm from the end wall. The half rule holds here too — with a single light it sits in the middle, and “half the spacing” is half the hallway width.
What to watch out for
- A cut-out must not hit a ceiling joist or support channel. Mark their positions before the ceiling is closed, or adjust them to the light grid.
- The number of lights depends not only on spacing but also on the light output and beam angle. If the manufacturer gives a recommended spacing, it beats any general rule.
- Above a kitchen counter or desk, move the lights over the work surface so you don't stand in your own shadow.
- Follow the manufacturer's instructions for installation depth, clearance from insulation and ventilation of the fitting.
Leave wiring and any changes to the electrical installation to a qualified electrician. The calculator only handles the layout — not lighting calculations or wiring.