UGR Estimator
Estimate Unified Glare Rating for your space based on room geometry, luminaire type, and surface reflectances. Check EN 12464-1 compliance.
Room & Luminaire
UGR Scale
EN 12464-1 Compliance
Frequently Asked Questions
What is UGR in lighting?
UGR (Unified Glare Rating) is a standardized metric (CIE 117:1995) that quantifies discomfort glare from luminaires. It ranges from 10 (imperceptible) to 30+ (intolerable). Lower UGR means less glare and better visual comfort.
What UGR do I need for an office?
EN 12464-1 specifies UGR ≤ 19 for standard offices and computer work. For technical drawing or CAD stations, UGR ≤ 16 is required. Meeting rooms can tolerate UGR ≤ 22 as the visual task is less demanding.
How can I reduce UGR?
Use deep recessed luminaires, louvered or microprismatic optics, indirect lighting, and higher ceiling reflectance. Positioning luminaires outside the direct field of view and increasing room surface reflectances also helps reduce UGR.
Does room size affect UGR?
Yes. Larger rooms with more luminaires visible tend to have higher UGR. The Room Cavity Ratio affects how surfaces contribute to the luminous environment. Narrow rooms and corridors often have lower UGR due to the limited viewing angle to luminaires.