Room Lighting Lumens

Estimate how much light a room needs by multiplying the floor area by the target brightness level in lumens per square foot (or foot-candle equivalent).

Measure length × width. Convert from square metres by multiplying by 10.764.
Living rooms: 10–20, kitchens: 30–50, task areas: 50–75.

Lighting recommendations vary; adjust for your needs.

Examples

  • 180 sq ft living room × 18 lm/ft² ⇒ 3,240 lumens
  • 120 sq ft kitchen × 40 lm/ft² ⇒ 4,800 lumens
  • 64 sq ft home office × 50 lm/ft² ⇒ 3,200 lumens

FAQ

How do I convert from lux recommendations?

1 foot-candle ≈ 10.764 lux. Divide the lux target by 10.764 to obtain lumens per square foot before using this calculator.

Does bulb efficacy affect the lumen target?

The lumen requirement stays the same, but higher efficacy LED lamps require fewer watts to hit the target brightness.

Should I oversize for dimming control?

Many designers overshoot the target by 10–20% and add dimmers so the space remains flexible for aging eyes or task-heavy days.

Additional Information

  • Lumens measure total light output. Foot-candles (lumens per square foot) indicate how bright the surface will appear.
  • Layer ambient, task, and accent lighting by splitting the total lumen target across multiple fixtures.
  • LED efficacy varies; divide the lumen target by the fixture lumen rating to determine the number of bulbs needed.

Related calculators

Reference the candela definition for compliance

When turning these lumen estimates into specifications, cite the candela deep dive, cross-check flux guidance with the lumen article, and confirm target illuminance with the lux explainer to show how your lighting plan aligns with ISO 80000-7 terminology and SI traceability.