The current draw of your lights is calculated using the amount of power your light needs (wattage) and system voltage using the following formula: Watts/Volts = amps or W/V = amps. An ampere or amp (A) is the standard unit for electrical current. A milliamp (mA) equals one-thousandth of an amp, or 1000 mA is equivalent to 1 A.
Choosing LED bulbs with the correct amperage ensures proper operation and prevents damage to your electrical system or the bulbs. See your vehicle owner's manual for amperage, wattage, and voltage information, or match the information on your existing bulbs.