How to Convert 250V to 110V

By Dan Keen ; Updated April 12, 2017

There are two basic voltage standards used in most countries around the world, namely 110 to 120 volts in the U.S., Central and South America, and some areas in the Pacific and the Caribbean, and 220 to 250 volts in most other countries. When traveling from one country to another, you may need a voltage converted if you plan on taking your hair dryer, laptop computer, cell phone charge, electric razor or other electronic appliances with you.

Find the wattage required to operate the appliance you intend to plug into a voltage converter. Converters are available with different wattage ratings; wattage is a measure of the power an appliance consumes. Most appliances have the wattage listed on a label pasted somewhere on the unit itself. If the wattage isn’t listed, the amperage will be given. You can calculate the wattage by multiplying the voltage times the amperage, or “amps.” For example, if the voltage is 120 volts and the appliance draws 2 amps, the wattage is 120 times 2, or 240 watts.

Multiply the wattage of your appliance times two. This is the minimum power wattage rating the converter should have to safely run your appliance. Purchase a voltage converter with the appropriate wattage rating that changes 220-250 volts to 110-120 volts. These are readily available at electronic stores. They are sometimes referred to as “foreign voltage adapters.”

Check the type of electrical plug used in the country where you will be traveling. Foreign voltage converters will either come with a set of interchangeable electrical plugs or the plugs will be available for the converter as a separate accessory.

Use a voltage transformer rather than a voltage converter if the device you plan to use will require a high wattage or will be used for extended periods of time. “Step-down” voltage transformers are bigger, bulkier and heavier than consumer voltage converters, but they are able to deliver more power and for longer periods of time.

Things Needed

  • Voltage converter
  • Foreign electrical adaptor plugs


Voltage converters and transformers change voltages, but do not change the frequency of the AC (alternating current). Most countries either use 60 Hertz (60 cycles per second) or 50 Hertz. Some appliances will work with either 50 or 60 Hertz, but check with the label on the appliance or refer to the owner’s manual.

About the Author

Dan Keen is the publisher and editor of a county newspaper in New Jersey. For over 30 years he has written books and magazine articles for such publishers as McGraw-Hill. Keen holds a degree in electronics, was chief engineer for two radio stations and taught computer science at Stockton State College.