Construction
Lighting Lumens Needed Calculator
Estimate total lumens needed for a room from floor area and target light level in lux.
The total lumens figure is a rough planning estimate of how much light the room needs in total.
Formula
Total lumens = floor area in square metres multiplied by target illuminance in lux. One lux equals one lumen per square metre.
How it works
Enter the room's floor area and how bright you want it, in lux. Kitchens and workspaces need more lux than bedrooms or hallways. Divide the total lumens by the lumens of one lamp to estimate how many lamps the room needs.
Worked example
For example, a room of 20 square metres at 300 lux needs 20 × 300 = 6,000 lumens.
FAQs
How many lux do rooms need?
Roughly 100 to 200 for bedrooms and living rooms, around 300 to 500 for kitchens and task areas.
Why is this only rough?
Wall color, ceiling height, fittings and shadows all change real brightness, so treat this as a planning figure.
How do I pick lamp count?
Divide total lumens by one lamp's lumen rating and round up, then spread lamps evenly.
Rough estimate only — consult a licensed professional for structural work before building.
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