How to Calculate the Right Lighting for Any Room
Good lighting transforms a room. Too dim and the space feels dreary and impractical. Too bright and it becomes harsh and uncomfortable. Our lighting calculator uses industry-standard lumen recommendations to tell you exactly how much light your room needs based on its size, purpose, and your preferences.
The calculation starts with lumens per square foot, which varies by room type. Kitchens and offices need 70–80 lumens per square foot for task work, while bedrooms and living rooms are comfortable at 30–50 lumens per square foot. Bathrooms need bright, even light at around 60–70 lumens per square foot, especially around the vanity. These guidelines come from the Illuminating Engineering Society (IES) and represent proven recommendations used by lighting designers.
Modern LED bulbs produce roughly 80–100 lumens per watt, making them five to six times more efficient than traditional incandescent bulbs. A single 10-watt LED produces about 800 lumens—the equivalent of a 60-watt incandescent. When planning recessed lighting, most standard 4-inch LED downlights output 600–800 lumens each, while 6-inch cans deliver 800–1,200 lumens.
Ceiling height matters too. Rooms with 9–10 foot ceilings need approximately 20% more lumens than standard 8-foot rooms, because light dissipates over distance. Vaulted ceilings may require pendant fixtures or higher-output downlights to compensate. After calculating your lighting plan, use RoomLab to visualize how different lighting styles look in your actual room.