Illuminance / Lux Level Calculator
How many fittings does the room really need? The utilisation factor is worked out from your room shape and surfaces instead of guessed — that one number is where most lux calculators lose their accuracy.
The room
m
m
Fitting down to the working plane, not floor to ceiling
m
Advanced / Custom Input — the surfaces
What happens in it?
Sets the recommended level from the standard body you picked above
Filled in from the space type — override for a specific task
lux
Advanced / Custom Input — the task
Minimum divided by average. 0.6 is the usual task-area figure.
From the luminaire datasheet. Typically about 1.5 for a direct fitting.
The light fitting
From the manufacturer — the luminaire output, not the bare LED
lm
Lumens per watt — used for the energy-code check
lm/W
Advanced / Custom Input — the fitting
From the luminaire’s own UF table. 0 to derive it from the room.
Direct fittings put more light down; indirect bounce it off the ceiling.
How dirty does it get?
Sets the maintenance factor
Filled in from the environment
Advanced / Custom Input — maintenance
LEDs at end of life. 0.85 to 0.95 typical.
0.80 to 0.95 depending on how clean the space is.
Otherwise the single figure above is used.
Result
Put in the room size and what happens in it, then press “Work out the fittings”.
Estimate only — verify with a licensed engineer or lighting designer and your local code authority before final design or installation.