How to convert 120v to 220v

Updated March 21, 2017

Electrical appliances and gadgets operate on different voltage depending on where you're located in the world. In North America and some other countries, 110-volt/120-volt is the standard whereas 220-volt/240-volt is standard for most other countries. Using devices with the incorrect voltage may result in irreversible damage to the product. For a variety of reasons ranging from world travel to international shopping, you may find yourself in a position where you need to convert electricity. North Americans should have no trouble converting 120V to 220V through the use of a step-up transformer.

Confirm that your device uses 120V by checking the information attached to the back or bottom of the device, on the electrical cord or the device's instruction manual. Note that in most situations 110V and 120V are interchangeable; thus, the following steps are applicable to 110V devices as well.

Check the device's information for its wattage. If amps are presented instead of watts, multiply the voltage and the amps to get the wattage value. For example, if a 110-volt device uses 0.5 amps, the calculation would be 110V (volts) x 0.5A (amps)= 55W (watts). Thus, the wattage for the item is 55 watts.

Look at the information located on the body of your step-up transformer to determine its wattage capacity. You can use your 120V device with the transformer as long as the device's wattage doesn't surpass 75 to 80 per cent of the transformer's wattage capacity.

Plug the step-up transformer into the 220V source, then plug the 120V device into the transformer. Turn on the transformer's power (often in the form of a switch) and your product is free to use without worry of damage due to voltage differences.


You can use multiple devices with the step-up transformer as long as the total wattage of the items does not exceed the wattage capacity of the transformer. For instance, you can safely use a 55-watt item and a 375-watt item with a transformer with a 500-watt or higher capacity.


Electrical plugs are not universal worldwide, so different countries may use different plugs despite using the same voltage. Additional plug adaptors can be used to modify the plug shape for use with the power source or the transformer.

Things You'll Need

  • 120-volt device
  • Step-up transformer
  • 220-volt power source
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About the Author

Dyna Whiting has been writing and editing health, science and technology related material for nine years. A lot of her experience was established in producing articles and business documents for organizations that are not proficient in English. She holds a Bachelor of Arts in psychology with a pre-medical background.