Lighting Calculator: How Many Lumens and Downlights Does a Room Need?
Most rooms are lit by guesswork, then end up either gloomy or floodlit. The honest way to plan it is to start from a light level, in lux, that suits how the room is used, multiply by the floor area to get the lumens you need, then divide by the output of each fitting. This calculator does that and suggests an even grid so the downlights are actually spaced right. The number nearly everyone misses is lumens, not watts: an LED spotlight can be 4W and still deliver 350 lumens.
Your room
Room size
How the room is used
The lux figures above are sensible ambient targets for the general lighting of each room; task spots over a worktop or a reading corner sit on top of that. The suggested grid keeps fittings evenly spaced, set half a gap in from each wall, so you avoid dark corners and the runway look of a single central row.
The Folio
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