Lighting Calculator
Pick the room type and the area — using a common recommended illuminance (lux) value for that room use, see the required total lumens and the approximate wattage based on the typical efficiency of modern LED fixtures.
We typically respond within 24 hours.
Let's plan the right lighting layers together based on your space's natural light and intended useThis is a rough illustration using a common reference illuminance (lux) value for the selected room type and LED efficacy (~90 lm/W); actual needs vary with natural light, surface colors, and task-lighting layers.
How is the required illuminance for a room calculated?
Illuminance (lux) measures the amount of light falling on a surface, and has a recommended range that varies with the room's use: visually demanding tasks like reading or work call for higher lux, while resting areas need lower, softer lighting. The required total light output (lumens) is roughly calculated as room area (m²) × recommended lux value.
The tool above uses a common lighting guideline value for your selected room type to show the required total lumens, plus the approximate wattage based on the typical efficiency of modern LED fixtures (~90 lumens/watt).
Common illuminance values by room type
Rest-focused rooms (bedroom, living room) aim for lower, warmer lighting to create a relaxing atmosphere; work/prep-focused rooms (kitchen counter, home office) need higher lighting for visual accuracy and focus. Bathrooms sit at a medium-high level due to detail tasks like shaving or makeup.
This tool uses a common general (ambient) lighting reference value for each room type — actual needs vary with how much natural light the room gets, how reflective the wall/ceiling colors are, and additional layers like task lighting (e.g. under-cabinet LED strips).
From lumens to watts: why the conversion is approximate
Watts measure energy consumed; lumens measure light produced — the ratio between them (lumens/watt) varies significantly by lighting technology. Incandescent bulbs give only about 10-15 lm/W, while modern LED fixtures typically run around 80-100 lm/W. This tool uses a common middle value for LED (~90 lm/W); the actual lumens/watt figure for your chosen product is on its packaging and may differ from this estimate.
Let's plan the right lighting layers (general, task, accent) together based on your space's natural light, intended use and overall interior design.
Contact usFrequently Asked Questions
How is illuminance (lux) calculated?
Simple formula: Required Lumens = Area (m²) × Recommended Lux Value. For example, a 20 m² kitchen using a common reference of ~400 lux needs 20 × 400 = 8,000 lumens — roughly equivalent to 8,000 ÷ 90 ≈ 89 watts of LED lighting (assuming ~90 lm/W efficiency for modern LEDs).
Why do kitchens and home offices need higher lux?
Rooms where visually precise tasks happen — cutting, reading, writing — benefit from higher illuminance to reduce eye strain and improve accuracy; resting rooms like living rooms and bedrooms use lower, softer general lighting instead.
Does this tool also account for task lighting?
No. The tool only gives a rough total-lumens estimate for general/ambient lighting; task-lighting layers like under-cabinet LED strips or reading lamps are project-specific and not included in this calculation.
Why does the lumens/watt ratio vary by product?
This ratio (luminous efficacy) varies significantly with the lighting technology used (incandescent, halogen, fluorescent, LED) and the product quality. This tool uses a common middle value for modern LED fixtures (~90 lm/W); the exact figure is stated on your chosen product's packaging.