There are two ways of measuring light. You can measure the brightness of light at the source or you can measure the amount of light reaching an object. The amount of light energy released from an object is radiance. How much light is reaching an object is illuminance. Lumens measure illuminance. If you light a single candle, the amount of light that illuminates one square foot located one foot away from the candle is one lumen. A lumen is equal to one footcandle of light---another way of measuring illuminance. Lux is also a unit for measuring illuminance. It's the metric version, and is short for lumens per square meter.
Determine if the lumens in question are equivalent to footcandles. Because lumens are used in both the metric and standard system, it can create some confusion.
Multiply the lumens per square foot (footcandles) by 10.764 to determine the lumens per square meter or lux. For example three lumens per square foot is equal to 32.292 lux.
Multiply by one if lumens are given in lumens per square meter. In other words they are equivalent to lux.