The rule contractors use: divide your ceiling height by two, and that's your spacing in feet.
Eight-foot ceiling → lights four feet apart. Nine-foot ceiling → four and a half feet. Ten-foot ceiling → five feet.
For a 12 × 14 room with 8-foot ceilings, that means roughly three rows of three — nine lights — with the outer row about two and a half feet off the walls.
Where the rule breaks
Task areas need more. Over a kitchen counter or a desk, tighten spacing to three feet regardless of ceiling height. You're lighting a work surface, not a room.
Dark surfaces eat light. Walnut cabinets, charcoal walls, or dark flooring absorb a substantial amount of what you put out. Add one or two fixtures, or step up in lumen output.
Vaulted ceilings change everything. The spacing formula assumes a flat ceiling. On a slope you need fixtures rated for the pitch, and beam spread matters more than count.
Don't light the walls by accident. Recessed cans placed closer than 24 inches to a wall will wash it — sometimes intentional, usually not. Keep them 24–30 inches off unless you're deliberately grazing artwork.
Quick reference
| Room size | 8 ft ceiling | 9–10 ft ceiling |
|---|---|---|
| 10 × 10 | 4 lights | 4 lights |
| 12 × 12 | 6–9 lights | 4–6 lights |
| 12 × 14 | 9 lights | 6 lights |
| 14 × 16 | 12 lights | 9 lights |
| 16 × 20 | 16 lights | 12 lights |
Then check total lumens
Spacing tells you placement. Lumens tell you whether the room is actually bright enough.
- General living space: 20 lumens per square foot
- Kitchen: 30–40 per square foot
- Bathroom vanity: 70–80 per square foot
A 12 × 14 living room is 168 square feet, so about 3,400 lumens total. Nine fixtures at 650 lumens each gets you 5,850 — comfortably bright, and you'd want them dimmable.
One thing worth doing: put them on a dimmer. Recessed lighting sized for daytime is almost always too much at night.