Calculate recessed-light spacing based on ceiling height and fixture diameter.
Spacing basis
Usage Tip
For task areas like a kitchen counter, tighten the spacing; for general ambient light the half-height rule works well.
first light from wall = spacing ÷ 2
The spacing is center to center; larger fixtures can sometimes be spaced a little wider.
How far apart should recessed lights be?
The fast answer is the rule of thumb: space recessed lights about the ceiling height divided by two. An 8 ft ceiling gives roughly 4 ft between cans, a 10 ft ceiling about 5 ft. But that rule ignores the one thing that actually decides how far the light spreads — the beam angle. A narrow 24-degree beam throws a tight pool and needs cans closer together; a wide 60-degree beam washes a big circle and can sit further apart. This calculator uses both: the ceiling height sets the baseline, the beam refines it, and then it lays the fixtures on a grid with the right distance from the walls.
The spacing rule and when it works
Ceiling height divided by two is a solid starting point for general ambient lighting with a typical 36-degree downlight. It works because a fixture mounted higher spreads its pool wider, so the spacing should grow with the ceiling. Where it breaks down: very narrow beams (which need tighter spacing), task areas that want more overlap, and accent or wall-wash layouts that follow the wall rather than a grid. Treat the rule as the baseline and let the beam angle and room type adjust it.
Beam angle and spacing
The beam angle sets the diameter of light each fixture lays on the floor, which is what really governs spacing:
| Beam | Spread | Spacing |
|---|---|---|
| 15° to 24° | Narrow accent | Tight — cans closer |
| 36° | General | Moderate — the rule of thumb |
| 50° to 60° | Wide wash | Wide — cans further apart |
Recommended light levels
Target footcandles by room, which guides how tightly to overlap the pools:
| Room | Footcandles |
|---|---|
| Living room / bedroom | 10 to 20 |
| Kitchen | 30 to 50 |
| Office | 30 to 50 |
| Workshop | 50 to 100 |
Distance from the wall
The first row should sit about half the fixture spacing from the wall — commonly 2 to 3 feet. Too close and you get harsh scallops of light running down the wall; too far and the wall reads dark and the room feels like it has a shadowy border. If you are lighting art or a feature wall on purpose, that row moves closer, around 18 to 30 inches, to wash the surface deliberately.
Common mistakes
- Too many fixtures — the ceiling turns into a grid of glare and the room feels like a surgical suite.
- Too few fixtures — dim pools with dark gaps between them, the dreaded cave effect.
- Wrong spacing — uneven gaps that make the light look accidental.
- Ignoring wall distance — cans too far from the walls leave the edges of the room gloomy.
Frequently asked questions
How far apart should 6 inch recessed lights be?
About 4 to 6 ft for general lighting — roughly the ceiling height divided by two, adjusted for beam angle.
How many recessed lights do I need?
Divide each room dimension by the spacing and round, then multiply. A 15 by 20 room at 5 ft spacing lands around 12 cans.
How far from the wall should recessed lights be?
About half the spacing, often 2 to 3 ft, so the walls are lit without scalloping.
What beam angle for recessed lighting?
About 36 degrees for general rooms; narrower for high ceilings or accent, wider for low ceilings and wall washing.
Can recessed lights be too close together?
Yes — over-spacing them tight creates flat, glary light and wastes fixtures. Even spacing at the right distance beats sheer quantity.
Does ceiling height change recessed spacing?
Yes, it is the biggest factor. Higher ceilings spread each pool wider, so the cans space further apart.
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Coming soon: Lux and Footcandle calculators
Estimates use beam-spread geometry and common spacing rules for planning and education. Real layouts depend on fixture optics, ceiling reflectance, furnishings, joists and other ceiling obstructions, and personal preference for brightness. Confirm critical layouts with a photometric plan, and have wiring done by a qualified person to local code.