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Room lighting (lumens) calculator
Room size and use to the total light it needs, in lumens, and how many fixtures that takes.
How the math works
Lighting designers plan in foot-candles: the light that lands on a surface. Multiply the square footage by the foot-candles a room needs and you get lumens. Kitchens and offices want 30 to 60 foot-candles, bathrooms 70 to 80 at the vanity, living rooms and bedrooms only 10 to 20.
Lumens, not watts
LED fixtures are rated in lumens. A typical 60-watt-replacement LED bulb gives about 800 lumens; a 4" recessed light gives 600 to 800; a vanity bar gives 1,500 to 3,000.
Layer the light
Hit the total with more than one layer: ceiling lights for general light, under-cabinet or pendant light over the work surfaces, and sconces or lamps for the evening. Put each layer on its own switch or dimmer.
Common questions
How many lumens for a kitchen?
Roughly 30 to 40 lumens per square foot of general light, plus task lighting over the counters. A 12 by 14 foot kitchen needs about 5,000 to 6,700 lumens.
How many lumens for a bathroom?
About 70 to 80 lumens per square foot around the vanity, where you need it for grooming. Put the main fixture on a dimmer for night use.
Related tools & pages
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