Lighting lumen method
Estimate luminaire quantity and connected load using photometric utilisation and maintenance factors you enter.
Enable JavaScript for live calculations. Read the method and default example below.
Method and assumptions
- N = ceil(target lux × area / (lumens per luminaire × utilisation factor × maintenance factor)).
- Three-phase current assumes evenly distributed luminaires. Select the actual supply arrangement and voltage.
Before using the result
- Average illuminance estimate only. Verify layout, uniformity, glare, emergency lighting and photometric performance separately.
Worked example
Illustrative default inputs. Enter your project values above.
- Room length
- 12 m
- Room width
- 8 m
- Height above work plane
- 2.2 m
- Target average illuminance
- 500 lux
- Lumens per luminaire
- 4000 lm
- Input power per luminaire
- 36 W
- Utilisation factor
- 0.6
- Maintenance factor
- 0.8
- Luminaire power factor
- 0.9
- Supply arrangement
- Single phase / two-wire load
- Supply voltage
- 230 V
Default results
- Luminaires required
- 25
- Connected input power
- 900 W
- Estimated circuit current
- 4.35 A
Choose a reference or send your BOQ
Compare relevant product families, then confirm the exact rating, control supply and duty. Price and availability are confirmed with your enquiry.
Technical references
These references support planning. The exact model documentation and a project-specific engineering review govern the final specification.