Lighting Layering Calculator

This calculator estimates total light output for a room and then splits it across the three-layer lighting design approach (ambient, task, and accent) that professional lighting designers use instead of a single overhead fixture. It starts from a base lumens-per-square-foot figure specific to each room type — bathrooms and offices need the most light (45 lm/sq ft) for detail work and safety, kitchens need 35, living rooms 18, and bedrooms the least at 12 — then multiplies by your room's square footage. Two adjustments follow: ceilings taller than 8 feet add 10% more required lumens per extra foot of height, since light has to travel farther and spreads out more before reaching the floor plane, and natural daylight level reduces the total by 15% for "some" natural light or 30% for "abundant" light, since sunlight offsets part of the artificial lighting need.

The resulting total is then divided among ambient, task, and accent layers using a ratio tailored to the room type — kitchens and offices skew toward task lighting (45%) for close work, bedrooms and living rooms lean ambient (60%) for general comfort, and bathrooms split more evenly. Finally, it converts total lumens into an approximate fixture count (assuming ~800 lumens per typical fixture) and LED wattage (assuming ~90 lumens per watt, typical of modern LED efficiency). These are planning-stage estimates based on averages, not a photometric layout — actual fixture placement, beam angle, wall and ceiling reflectance, and dimming all affect how much of that calculated lumen output you actually perceive in the room.