Footcandle Calculator: Lighting Layout and Lighting Power Density

Footcandles or lux across a room from luminaire type, lumens, mounting height and layout. Load IES files and check LPD against the IECC.

Point-by-point illuminance grid on the work plane, plus reflected light from the room surfaces
Average, maximum and minimum footcandles with max:min and avg:min uniformity
Generic downlights, troffers, linear pendants and high bays, or a manufacturer IES (LM-63) file
Number of luminaires needed for a target light level
Lighting power density against IECC 2021 and 2024 space-by-space allowances
Shaded plan and section diagrams

How to use

Enter the room length, width and ceiling height.
Enter the mounting height above the floor (the ceiling height for recessed luminaires) and the work plane height: 2'-6" for desks, 0 for floors and corridors.
Pick a luminaire type, or choose From an IES file and open the .ies file from the manufacturer’s product page. Adjust the lumens and watts to the product you are using.
Set the rows and columns of the layout. Luminaires are spaced evenly, with half a space at each wall.
Choose the ceiling / wall / floor reflectances and the light loss factor (0.85 is typical for LED with periodic cleaning).
Read the maintained average, the uniformity and the shaded plan. Hover the plan to read single points. Enter a target to see how many luminaires it takes.
Pick the energy code and space type to check the lighting power density.
This is a schematic estimate: luminaires are treated as point sources and reflected light is averaged over the room. Confirm final designs in AGi32 or DIALux.
Length fields accept the same entries as the Feet and Inches Calculator: 9' 6, 7 3/4", 2743mm or 3m + 6'. A plain number means inches, or millimeters when the Units panel is set to metric.