Use this calculator for an early planning estimate, then compare the result with fixture photometric data and conditions in the actual room. It does not replace a lighting design, product instructions, electrical calculations or applicable codes.

Lux to Lumens Calculator

Convert target lux and metric area into an estimated total lamp-lumen requirement.

Planning estimate only. Confirm photometric, product, code and electrical requirements before installation.

Formula and assumptions

Lamp lumens = lux × square meters ÷ utilization factor ÷ light-loss factor. The calculation assumes the numbers entered are compatible and that fixture output is delivered uniformly. Real results change with optics, mounting height, surface reflectance, daylight, dimming, dirt, aging and obstructions. Use manufacturer photometric files for a design decision.

How to use the result

Treat the result as a starting range. Test more than one scenario, document the inputs and compare the estimate with the rated lumens, wattage, beam distribution and control compatibility of the exact product. A mock-up is especially useful where glare, shadows or visual comfort matter.

Important limits

Lumens describe emitted light; lux and footcandles describe light arriving on a surface. Watts describe electrical input, not brightness. A simple calculator cannot predict uniformity or glare. Consult a qualified lighting professional for demanding visual tasks and a licensed electrician for new wiring, circuit changes, wet locations or any work beyond safe user-serviceable tasks.

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