Calculate how many recessed lights you need, optimal spacing, total lumens, wattage, and electricity cost — with a visual room layout showing exact fixture positions.
Enter the room you want to light
Choose your recessed light type and bulb output
Flood=60°, Spot=25-38°
Target illuminance and efficiency factors
Calculated optimal grid placement, shown to scale
Same room at different illuminance targets
| Target fc | Fixtures | Total Watts | Monthly Cost | Hardware Cost |
|---|
Fixtures Needed
Spacing
Total Lumens
Total Wattage
Monthly Cost
Hardware Cost
| Room Type | Min (fc) | Recommended (fc) | Task Level (fc) | Lux Equivalent |
|---|
Spacing Rule of Thumb
A quick rule: space fixtures apart by a distance equal to half the ceiling height. For an 8-ft ceiling, space lights 4 ft apart. This ensures overlapping cone coverage without dark spots.
Edge Distance
Keep the first row of lights at least 2 ft from walls. If you want to wash the walls with light (art, shelving), bring lights in to 18–24 inches from the wall for dramatic wall-wash effect.
Use Dimmers
Always install recessed lights on a dimmer circuit. LED dimmers (not incandescent dimmers) allow you to dial from full task lighting to ambient mood lighting. This extends bulb life and cuts energy use dramatically.