LED stands for Light Emitting Diode.

A watt is a unit of power used to quantify the rate of energy transfer from an LED product. It is equivalent to one joule per second. The calculation that is used to derive a watt is the voltage multiplied by the amperage. Basically it’s a way to track how much energy a product consumes.

The symbol for wattage is: w, for example:

4.8w

Lumens is the measurement of brightness that an LED product gives out as perceived by the human eye. It is important to consider the lumen output when purchasing an LED product as this will tell you just how bright the product is going to be.

The symbol for lumens is: lm, for example:

260lm

This is a value that is calculated by measuring the lumen output, then dividing that number by the wattage of the product. For example, an LED product that has a lumen output of 300lm per metre and a wattage of 3w per metre would have a luminous efficacy of 100lm/w.