Lumen Calculator (Lux/Foot-Candles, Room Size, Light Levels) | Stetra Lighting

Lumen Calculator (Lux/Foot-Candles, Room Size, Light Levels)

Use this lumen calculator to estimate the luminous flux (lumens) required for a room. Enter room dimensions, mounting height, and the illuminance target (lux or foot-candles). Results update automatically.

Auto-updating Metric + Imperial First approximation

Calculator

Auto updates

Units

Choose Metric or Imperial. Values convert automatically.

Room Dimensions

Enter room size and mounting height (fixture to work plane).

Lighting Target

Enter the required illuminance. Toggle between fc and lux.

Updates automatically. No “Calculate” button needed.
Room Index
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Utilisation Factor (UF)
—
Target Level
—
Luminous Flux Needed
— lm
Important: This estimate is based on simplified assumptions. For verified lux/fc targets, uniformity, and glare control, use IES-based photometry.

FAQ

Calculators
How accurate is this lumen calculator?

This is a first approximation. Real results depend on fixture optics, distribution, reflectances, and room geometry. For verified lux/fc, use IES-based photometry.

Related tool: IES Viewer →
What inputs affect the result the most?

Room size, target lux/foot-candles, and mounting height. Mounting height changes room index, which affects utilisation factor.

When should I order a photometric plan?

When you need verified targets for compliance, permitting documentation, or coordination across multiple fixture types using real IES files.

Related tool: Voltage Drop Calculator →

Common Lighting Levels

Quick reference

Use these typical targets as a starting point when entering values in the lumen calculator. Final requirements depend on task, finishes, ceiling height, and local code.

🏠 Residential (Typical Targets)
Living Room10–20 fc (100–200 lux)
Kitchen30–50 fc (300–500 lux)
Bedroom10–20 fc (100–200 lux)
Bathroom20–50 fc (200–500 lux)
Dining Area10–30 fc (100–300 lux)
Hallways & Stairs5–15 fc (50–150 lux)
Patio5–10 fc (50–100 lux)
Garage10–30 fc (100–300 lux)
🏢 Commercial / Industrial (Typical Targets)
General Office Workspaces30–50 fc (300–500 lux)
Conference Rooms20–30 fc (200–300 lux)
Reception Areas20–30 fc (200–300 lux)
Break Rooms / Lounges10–20 fc (100–200 lux)
General Storage Areas10–20 fc (100–200 lux)
Loading Docks20–50 fc (200–500 lux)
Assembly / Detailed Work50–100 fc (500–1,000 lux)
Inspection Areas100–200 fc (1,000–2,000 lux)
Tip: If you don’t know what to choose, start in the middle of the range. Then adjust based on ceiling height, fixture optics, and how “bright” you want the space to feel. For permit-ready plans and verified targets, Stetra Lighting can produce a full photometric calculation.