Recessed Lighting Calculator

Your details

The longest wall dimension of the room.
ft
The shorter wall dimension of the room.
ft
Standard residential ceilings are 8-9 ft. Higher ceilings need more fixtures for the same foot-candle level.
ft
Sets the target lumens per square foot based on IES lighting standards for each space type.
Check the bulb or LED module package. Common 6-inch LED retrofit cans output 650-900 lm. Higher-output trims reach 1,200-1,500 lm.
lm
LED recessed lights typically use 8-15 W. Older halogen PAR cans used 50-90 W.
W
6-inch is the most common size for general ambient lighting in residential spaces.
The U.S. residential average is about $0.16/kWh (2024 EIA data). Check your bill for your local rate.
$/kWh
How many hours per day the recessed lights are on on average.
hrs/day
Fixtures neededWell-lit for living areas
9lights

Number of recessed fixtures for even coverage at your target brightness

Center-to-center spacing7.2ft
Wall offset (first fixture)3.6ft
Layout rows3
Layout columns3
Total lumens delivered7,200lm
Foot-candles achieved37.5fc
Total wattage90W
Estimated annual energy cost26.28USD
Columns3
Rows3
Total fixtures9

9 recessed fixtures for this room, arranged in a 3 x 3 grid.

  • Your living room targets 20 lm/ft, a standard IES recommendation for that space type.
  • Place fixtures 7.2 ft apart center-to-center, with the first row 3.6 ft from the wall to avoid dark edges.
  • Your layout delivers about 38 foot-candles across the floor - meeting the target for this room type.
  • Running 9 x 10 W LED fixtures at your usage pattern costs roughly $26 per year in electricity.
  • 6-inch (general ambient) trim is your selected size. Use IC-rated (insulation-contact) housings wherever insulation may touch the can - this is a fire-safety requirement in most building codes.

Next stepFinalize your layout by marking fixture centers on a ceiling diagram and confirming joist locations with a stud finder before cutting. Add a dimmer switch rated for LED loads to save energy and adjust mood lighting.

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