How this calculator works
First work out how much light the room needs: the area times the lumens per square foot for the kind of room (15 for a living room, 35 for a kitchen). Divide by the lumens each light gives to get the number needed for brightness. Then check that the spacing is not too wide: recessed lights light a cone below them, so for even light they should be no farther apart than about the ceiling height. The calculator takes the larger of the two counts and lays the lights out in a grid that is as square as the room allows.
Worked example: a 14 × 12 ft living room (168 ft²) needs 2,520 lumens, which is 3.2 lights of 800 lumens; with an 8 ft ceiling and the standard spacing the room needs 4 lights in 2 rows of 2, 7.0 ft apart along the length and 6.0 ft across, with the first lights 3.0 ft from the walls. As a kitchen it needs 9 lights, with a 10 ft ceiling 4, with closer spacing 6, a 20 × 20 ft room needs 9 and a 10 × 10 ft one 4.
Recessed lights for common rooms (living room, 800 lumen lights, 8 ft ceiling)
The grid and spacing at the standard setting.
| Room | Lights | Grid | Spacing |
|---|---|---|---|
| 10 × 10 ft | 4 | 2 × 2 | 5.0 × 5.0 ft |
| 12 × 12 ft | 4 | 2 × 2 | 6.0 × 6.0 ft |
| 12 × 14 ft | 4 | 2 × 2 | 6.0 × 7.0 ft |
| 14 × 16 ft | 6 | 2 × 3 | 7.0 × 5.3 ft |
| 16 × 20 ft | 6 | 2 × 3 | 8.0 × 6.7 ft |
| 20 × 24 ft | 9 | 3 × 3 | 6.7 × 8.0 ft |
Tips before you buy
- A common rule of thumb is to space recessed lights at about half the ceiling height, or up to the full ceiling height for general light, and no more than twice the ceiling height for accent.
- Put the first row about half the spacing from the wall, or about 3 ft away for wall washing. Lights too close to a wall make scallops of light.
- Light the tasks: add lights over counters, islands, desks and mirrors, and keep them out of your own shadow.
- Use a dimmer rated for LEDs, and choose the color temperature (2700 K warm for living areas, 3000 to 4000 K for kitchens and baths).
- Check the housing is IC-rated where it touches insulation, and airtight in the ceiling to a heated attic.
Tools & materials for this project
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Frequently asked questions
How many recessed lights do I need for a 12x14 room?
4 lights of 800 lumens, in 2 rows of 2, for a living room with an 8 foot ceiling. A kitchen of that size needs 9.
How far apart should recessed lights be?
About the height of the ceiling for general light, and closer (three-quarters of the height) if you want it very even. For an 8 ft ceiling that is 6 to 8 feet. This room works out at 7.0 by 6.0 feet.
How far from the wall should recessed lights be?
About half the spacing, so 3.0 to 3.5 ft here. Closer to the wall (1 to 2 feet) washes the wall with light, and farther gives scallops.
How many lumens per recessed light?
A 6 inch LED gives 600 to 1,000 lumens and a 4 inch one 400 to 700. Choose dimmable lights so you can set the level.
How many recessed lights can go on one circuit?
An LED light uses about 9 watts, so a 15 amp circuit (1,440 watts continuous) carries well over a hundred. The limit is usually the code and the dimmer, not the circuit.
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Estimates only. Results assume standard materials and simple shapes. Supplier products vary, and the final call on quantity, structure and safety is yours. Check your local code and your supplier's guidance before ordering.