lighting

How to Calculate a Lighting Layout: Lumens & Recessed Lights (2026)

How to Calculate a Lighting Layout: Lumens & Recessed Lights To calculate a lighting layout, multiply room square footage by the foot-candles the room needs to get total lumens, divide total lumens by your fixture's lumen output to get the number of fixtures, then set grid spacing from the ceiling height (maximum spacing = ceiling height x 1.0-1.5). For our median room, 16 ft long x 12 ft wide = 192 sq ft, a general 30 foot-candle target needs 192 x 30 = 5,760 lumens, which is 5,760 / 800 = 7.2, rounded up to 8 fixtures at 800 lumens each. With an 8-ft ceiling, max spacing is 8-12 ft, so a 4-by-2 grid lands the columns 4 ft apart and the rows 6 ft apart. Run the numbers for your own room with the Lighting Layout Calculator(/construction/lighting-layout-calculator). When I relit my own 16 x 12 ft living room two...