The ceiling height rule
A simple rule gives an even layout for general lighting with recessed lights, also called can lights or pot lights:
- space the lights about half the ceiling height apart: 4 ft apart under an 8 ft ceiling, 5 ft apart under a 10 ft ceiling;
- place the first row about half that distance from the walls, so the walls are lit as evenly as the room’s center.
The calculator rounds up the number of lights along each wall and spreads them evenly, so the actual spacing is equal to or a little less than the target.
Example
A 14 × 12 ft room with an 8 ft ceiling:
- target spacing: 8 ÷ 2 = 4 ft;
- 14 ÷ 4 = 3.5, rounded up to 4 lights along the length, 3.5 ft apart;
- 12 ÷ 4 = 3 lights along the width, 4 ft apart;
- total: 12 recessed lights, starting about 1.75 ft from the end walls and 2 ft from the side walls.
With 650-lumen fixtures, the room gets 7,800 lumens, roughly 20 to 25 foot-candles on the floor.
How much light?
| Room | Typical target |
|---|---|
| Living room, bedroom | 10 to 20 foot-candles (100 to 200 lux) |
| Kitchen, bathroom vanity | 30 to 50 foot-candles (300 to 500 lux) |
| Home office, workshop | 50 foot-candles (500 lux) or more |
Use dimmers to adjust a bright layout to the mood. Task lighting, such as under-cabinet lights in a kitchen, works better than adding more ceiling cans.
Choosing the fixtures
- Size: 4-inch fixtures give a tighter, more modern look; 6-inch fixtures spread more light.
- Beam angle: a wider beam needs fewer fixtures; narrow beams suit accent lighting.
- Color temperature: 2700 K to 3000 K feels warm for living spaces; 3500 K to 4000 K suits kitchens and workspaces.
- Ratings: in an insulated ceiling use IC-rated, airtight fixtures; in showers use fixtures rated for wet locations.
Accent and wall washing
To light artwork or a feature wall, place fixtures about 1.5 to 3 ft from the wall, closer for low ceilings, and use adjustable trims. Avoid placing a can directly above a seat or bed, where it shines into people’s eyes.
Have a licensed electrician check the circuit capacity and do the wiring where your local code requires it.