How Are LED Lumens Calculated?

How Are LED Lumens Calculated? A lumen is a unit measurement of light. To determine the needed lumens, you will need to multiply your room square footage by your room foot-candle requirement. For example, a 100 square foot living room, which needs 10-20 foot-candles, will need 1,000-2,000 lumens. How many lumens is a 4 foot