18×20 room:
how many lights?
9–30fixtures A 18×20 ft room is 360 square feet. How many lights it needs depends entirely on what happens in it — a kitchen is lit to roughly twice the level of a bedroom, so the same footprint ranges from 9 to 30 fixtures at 800 lumens each.
The footprint does not decide the count. The target illuminance does, and that is set by what the room is for.
SOURCE·IES lumen-method recommendations·published recommendations, quoted as ranges·REVIEWED JUL 2026
Plan above: the 18×20 ft footprint laid out as a living room at 150 lux, with iso-lux contours at 32 / 21 / 11 lux.
Schedule · by useOne 18×20 footprint, twelve commissioning targets
| Room type | Target | Total lumens | Fixtures | Grid | Spacing |
|---|---|---|---|---|---|
| Kitchen | 300 lx | 18,853 lm | 25 | 5 × 5 | 4′ × 3.6′ |
| Living room | 150 lx | 11,063 lm | 16 | 4 × 4 | 5′ × 4.5′ |
| Bedroom | 100 lx | 7,375 lm | 9 | 3 × 3 | 6.7′ × 6′ |
| Bathroom | 200 lx | 14,751 lm | 20 | 5 × 4 | 4′ × 4.5′ |
| Home office | 300 lx | 19,438 lm | 25 | 5 × 5 | 4′ × 3.6′ |
| Dining room | 150 lx | 9,719 lm | 12 | 4 × 3 | 5′ × 6′ |
| Garage | 150 lx | 11,063 lm | 16 | 4 × 4 | 5′ × 4.5′ |
| Hallway | 100 lx | 7,375 lm | 9 | 3 × 3 | 6.7′ × 6′ |
| Laundry | 200 lx | 12,569 lm | 16 | 4 × 4 | 5′ × 4.5′ |
| Basement | 150 lx | 11,063 lm | 16 | 4 × 4 | 5′ × 4.5′ |
| Workshop | 400 lx | 25,138 lm | 30 | 6 × 5 | 3.3′ × 3.6′ |
| Nursery | 100 lx | 7,375 lm | 9 | 3 × 3 | 6.7′ × 6′ |
At 800 lumens per fixture and an 8 ft ceiling. Open a room type for other fitting outputs, other ceilings and its own contour sheet.
SOURCE·IES lumen-method recommendations·published recommendations, quoted as ranges·REVIEWED JUL 2026
QueriesWhat this footprint is usually asked
How many recessed lights for a 18x20 room?
It depends what the room is for. A 18×20 ft (360 sq ft) living room needs about 16 fixtures at 800 lm; the same footprint as a kitchen needs about 25, because a kitchen is lit to roughly double the level. Pick the room type for the real answer.
How many square feet is a 18x20 room?
360 square feet, or 33.4 square metres.
