Lumen Calculator
Use this lighting planning workflow to estimate lumens for a room before checking fixture photometrics and project criteria.
- Required lumens
- lm
- Estimated fixture count
- fixtures
- Target illuminance
- lux
- CU x LLF factor
- x
Calculation details
- Calculation basis
- Design boundary
Recent results
Formulas
- Required lumens = area x target footcandles / (CU x LLF)
- Fixture count = ceiling(required lumens / lumens per fixture)
- Target lux = target footcandles x 10.76390625
Use this calculator
Estimate required lumens and fixture count from room area, target footcandles, utilization, light loss, and lumens per fixture.
Read the result
Review the calculated values with their displayed units and assumptions. The result is a planning aid for the stated inputs, not a final equipment or installation decision.
Check before final work
This lumen estimate is for early lighting planning. It does not replace fixture photometrics, spacing checks, glare review, energy-code review, or project lighting design.
FAQs
Does this replace a photometric layout?
No. It estimates lumens from area and target illuminance. Fixture placement and photometric design require more data.
Why include CU and LLF?
Those factors account for how much light reaches the work plane and how much output is expected after losses.