Lux to Lumens Engineering Converter

Summary

Enter illuminance (lux or foot-candles) and area to convert to lumens, or reverse — with optional utilization factor for real fixture design.

How it works

1. Select the conversion direction: lux → lumens or lumens → lux.
2. Choose the illuminance unit (lux or foot-candles) and the area unit (m² or ft²).
3. Enter the illuminance value and the surface area.
4. Optionally adjust the utilization factor (0.1–1.0) to model real-world fixture losses.
5. The result updates instantly, showing the formula and a quick reference table.
6. Use the multi-zone table to total lumens across several spaces at once.

Use cases

• Calculate the total lumen package needed to illuminate an office floor to 500 lux.
• Convert foot-candle specs from US luminaire datasheets to SI lux and lumens.
• Size LED fixtures for a warehouse by working backwards from a required lux level.
• Apply a utilization factor to get a realistic lumen budget including fixture losses.
• Verify that a lighting design meets IESNA or EN 12464 recommended levels.
• Sum lumen requirements across multiple rooms or zones in one session.
• Check whether an existing fixture's lumen output delivers the target illuminance.
• Teach photometry concepts with live formula display and reference data.

Frequently Asked Questions