Recessed Lighting Calculator
Plan recessed lights by room size, target foot-candles, fixture lumens, CU, LLF, beam angle and spacing criterion. Get rows, columns, offsets, maintained light and energy cost.
Project inputs
Change any value to update the result. Units, boundaries and conditional fields are validated by this calculator’s own engine.
Recessed Lighting Calculator results
How to use the recessed lighting calculator
This recessed lighting calculator uses a dedicated engine, live visual and explanations specific to this problem. Review the assumptions before using the output for purchasing, design, grading, pricing or operational decisions.
A lighting plan based on maintained illumination
This recessed lighting calculator uses the lumen method rather than a fixed “one light every few feet” rule. Room area and target foot-candles determine the lumens needed at the work plane, while coefficient of utilization and light loss factor account for how much rated output reaches the space over time.
Count and grid placement
The tool rounds fixture demand upward and searches for a row-by-column grid suited to the room proportions. It checks center-to-center spacing against mounting height, beam angle and spacing criterion, then calculates equal wall offsets so the grid remains centered.
Use realistic fixture data
Use delivered lumens, wattage, beam angle and spacing criteria from the actual luminaire data whenever available. Dark finishes, tall ceilings, cabinets, sloped ceilings, task planes and daylight may require a photometric plan beyond a simple room-average calculation.
Electrical and design caution
The result is a planning estimate. Follow U.S. electrical codes, insulation-contact ratings, wet-location listings, dimmer compatibility, fire assemblies and local permit requirements. A qualified lighting designer or electrician should confirm final placement and circuit loading.
Recessed Lighting Calculator questions
How far apart should recessed lights be?
Spacing depends on mounting height, beam distribution and the luminaire’s spacing criterion. The calculator limits both row and column spacing and shows centered wall offsets.
What are CU and LLF?
Coefficient of utilization estimates the share of lamp lumens reaching the work plane. Light loss factor accounts for depreciation, dirt and other maintained-output losses.
Can this calculate kitchen task lighting?
It can estimate an average kitchen target, but counters and work surfaces often need dedicated task lights. Treat cabinet shadows and local task illumination separately.