Illuminance Converter

Divide lux by 10.764 to get foot-candles. A typical office requires 300-500 lux (28-46 foot-candles). OSHA recommends a minimum of 30 foot-candles (323 lux) for general office work and 50 foot-candles (538 lux) for detailed tasks.

Indoor portrait photography typically needs 500-1,000 lux. Product photography requires 1,000-2,000 lux for sharp detail. Direct sunlight provides about 100,000 lux, overcast daylight about 10,000-25,000 lux and a well-lit studio about 2,000-5,000 lux.

A phot is a CGS unit of illuminance equal to 10,000 lux. It was commonly used in older scientific literature but has been largely replaced by lux (the SI standard). Direct sunlight is about 10 phot, while typical indoor lighting is 0.03-0.05 phot.

OSHA standards vary by task: warehouses need 5-10 foot-candles (54-108 lux), general offices need 30 foot-candles (323 lux), detailed assembly work needs 50-100 foot-candles (538-1,076 lux) and surgical suites need 1,000+ foot-candles (10,764+ lux).

Lumens measure total light output from a source, while lux measures how much light hits a surface (lumens per square meter). A 1,000-lumen bulb produces about 250 lux at 1 meter distance. Foot-candles are lumens per square foot, used primarily in the US.