KelvinPlanHow much light each room needs, and what colour it should be.

Recessed lights for a 14 × 18 ft dining room with a 11 ft ceiling

Recessed lights needed
9lights
3 × 3 grid, about 4.7 ft apart in a 14 × 18 ft dining room
Layoutacross the 14 ft dimension × along the 18 ft dimension3 × 3
Spacing (rule of thumb)half of the 11 ft ceiling5.5ft
Actual spacing to mark outafter rounding to whole fixtures4.7 × 6ft
First light from the wallhalf a spacing — closer washes the wall, further leaves dark corners2.3 × 3ft
Room area252ft²
Target light levelambient around a fixture over the table20fc
Total lumens needed5,040lm
Lumens per fixtureabout 7 W each in LED560lm
Room width
14 ft
Room length
18 ft
Ceiling height
11 ft
Room
dining room

The grid

Spacing for recessed cans is ceiling height divided by two. A 11 ft ceiling gives 5.5 ft, which across a 14 × 18 ft room works out to a 3 × 3 grid — 9 lights.

Rounding to whole fixtures moves the real spacing to 4.7 × 6 ft. Mark the ceiling off those numbers, not off the rule of thumb. The first row sits 2.3 ft from the wall — half a spacing. Closer and you get a bright band down the wall; further and the corners go dark.

What to buy, not just how many

252 ft² at 20 footcandles needs 5,040 lumens in the room, which is 560 lumens per fixture — around 7 W in LED.

That is the number to shop by, and it is the one most layout calculators leave out. A 4″ LED downlight typically runs 600–800 lm; a 6″ runs 800–1,200 lm.

Before you cut

Find the joists first. A 3 × 3 grid rarely lands clear of framing on the first attempt, and shifting a can six inches to miss a joist is invisible once the trim is on. Put the whole layout on a dimmer while the wiring is open — it costs almost nothing then and cannot be added cheaply later.

Notes

  • The spacing rule is ceiling height ÷ 2, which gives 5.5 ft here. Rounding to whole fixtures moves it to 4.7 × 6 ft — mark the ceiling off the real numbers, not the rule.
  • 560 lumens per can is the figure to shop by. A 4″ LED downlight typically runs 600–800 lm and a 6″ runs 800–1,200 lm, so you could drop to 4″ cans or dim these down.
  • 20 fc is an ambient level, which is what you want here. Recessed lights alone make a room look flat; the fix is lamps and wall light, not more cans.
  • Put them on a dimmer. It costs almost nothing at install, and it is the difference between a ceiling that works at dinner and one that works at 11pm.
  • Check the joists before marking. A 3 × 3 grid rarely lands clear of framing on the first try, and moving a can 6 inches to miss a joist is invisible once the trim is on.

Nearby sizes

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