The amp ratio of Christmas lights depends on the wattage and voltage of the lights. LED Christmas lights usually have low amperage requirements. On average, these lights consume around 0.02 to 0.05 amps per bulb. For example, a string of 100 LED lights could use approximately 2 to 5 amps in total. However, remember that this is a general estimate, and the specific amperage may vary depending on the product.