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Lighting Calculator

Estimate how many lamps you need for a room.

Lux indicates how much light reaches the room surface.
Check the lumen output printed on the lamp or product specification.
Advanced Settings
Represents how much of the lamp output effectively reaches the room area. Default: 0.70.
Allows for light reduction over time from ageing, dust and other losses. Default: 0.80.
Lighting Requirement
Lamps Needed
–
lamps
Room Area –
Desired Brightness –
Light Needed on Room Area –
Total Lamp Output Needed –
Calculated Number of Lamps –
Estimated Brightness –
Total Power –
Power per m² –
Room Area per Lamp –
How the Calculation Works

The calculator estimates the total light output needed from the room area and the desired brightness level. It then adjusts the requirement for normal light losses and divides the result by the lumen output of each lamp.

The final number of lamps is rounded upward because a fraction of a lamp cannot normally be installed. The calculator then estimates the brightness that the rounded number of lamps should provide.

Results are intended for preliminary lighting estimates. Actual lighting depends on room shape, ceiling height, lamp position, beam angle, wall and ceiling reflectance, daylight and product photometric performance. Detailed projects should follow applicable lighting standards and manufacturer data.