Skip to main content



The watt (W) is a convenience unit to describe the amount of work that current can do, as a factor of voltage and amperage, and is defined as:

Watts = Volts * Amps

Common Wattages

Electrical CurrentVoltageAmperageWattage
Hair Dryer117V12A1,404W
60 Watt Incandescent Light Bulb117V~0.5A~60W
iPad/Tablet Charger5V~2A10W

Further Reading

For a much more in depth discussion regarding amps, see the wattage section in Part 2 of the Electronics Tutorial