Travel plug adapters and voltage converters

Two numbers decide whether your device is happy: voltage and frequency. Voltage is the pressure of the electricity — roughly 120 V in North America and Japan, and 220–240 V in most of Europe, Asia, Africa and Australia. Frequency is how often the current cycles per second: 60 Hz in the Americas and parts of Asia, 50 Hz almost everywhere else.

For modern electronics, voltage is the number that matters. A dual-voltage charger labelled 100–240 V handles both worlds. Frequency is usually a non-issue for chargers, laptops and LED lamps, because they convert AC to low-voltage DC internally. It matters for anything with a motor or a clock that runs off the mains: older alarm clocks may gain or lose time, and some motorised appliances run slightly faster or slower. It is rarely dangerous, just imprecise.

The dangerous case is a single-voltage heating appliance. A 120 V hair dryer on a 230 V supply draws far more current than it was built for, overheats within seconds and can burn out or trip the breaker. The reverse — a 230 V appliance on 120 V — usually just runs weakly or not at all, which is annoying rather than dangerous. Either way, an adapter alone does not fix it.

A converter is worth carrying only if you have a single-voltage device you cannot replace or leave behind. The most common case is a hair dryer or straightener bought at home for 120 V use and taken to Europe or Asia. Converters come in two broad kinds: transformer-style converters, which are heavy and handle higher wattages, and solid-state or triac converters, which are light and cheap but suit only heating devices and low wattages.

Wattage is the number to match. Look at the appliance label for watts (or volts × amps). A hair dryer can draw 1,200–1,800 W, which is beyond most travel converters; a straightener might be 40–60 W, which a small converter can handle. If your device's wattage is higher than the converter's rating, the converter will overheat or fail. Many travel converters also warn against use with electronics, because the modified output can damage sensitive chargers.

The honest advice for most trips: do not bring a converter. Buy a dual-voltage travel hair dryer or straightener (many are labelled 100–240 V with a switch), or use the one in the hotel. If you must convert, buy a converter rated well above your device's wattage and read the instructions before plugging anything in.

The simplest way to cut adapter clutter is to charge everything over USB. A single 30–65 W USB-C charger with the right plug can run a phone, tablet, camera and many thin laptops, and a multi-port charger covers a family's devices from one socket. USB-C Power Delivery negotiates the voltage automatically, so the same brick works from a US 120 V socket and a European 230 V socket as long as it is rated 100–240 V.

A short power strip is the other useful item. Choose one with a cable rather than a rigid block, so it reaches the desk or bedside table, and check that it is rated for the local voltage (most are 100–250 V). Plug the strip into the wall with your adapter, then plug your chargers into the strip. This also solves the common hotel problem of one usable socket behind the bed.

Power banks are charged over USB and carried in hand luggage, not checked bags, on most airlines. Capacity limits apply: many carriers cap lithium batteries at 100 Wh per battery without approval, and 160 Wh with airline approval. Check your airline's rules before you fly.

Prices vary by country and shop, but the ranges below are a reasonable planning guide for 2026. Buying before you fly is almost always cheaper than buying at an airport or hotel, and online marketplaces usually beat airport shops by a wide margin.

A single-country plug adapter is the cheapest option, a universal adapter costs a little more, and a converter is the most expensive and least useful item for most travellers. If you need several adapters for a family, a multi-pack of single-country plugs often costs less than one universal adapter and is less likely to be lost.

Some devices sit outside the simple rules. Electric toothbrush bases and shavers often come with dual-voltage chargers, but the charging stand may be single-voltage; check the base label, not just the brush. CPAP machines for sleep apnoea are usually dual-voltage, but some models need a specific power supply or a converter, so check the manual and consider a travel battery for flights.

Medical devices deserve extra care. If you travel with a powered medical device, ask the manufacturer for the voltage and frequency range and whether a converter is acceptable; do not guess. The same applies to older camera battery chargers, film equipment and anything with a motor.

Frequency-sensitive items are a smaller category: mains-powered clocks, some audio equipment and older motorised appliances. They will usually work, but may run fast, slow or hum. Battery-powered versions avoid the problem entirely. Finally, ships, trains and older buildings sometimes use unusual sockets or supply voltages; a universal adapter with a voltage indicator is a reasonable precaution, and asking the hotel in advance is better still.

Work through a short checklist a week before departure. First, list every device you are taking and note its voltage range from the label. Second, identify the plug type or types for each destination, including any stopovers where you might charge something. Third, decide what you will do about single-voltage heating tools: leave them, replace them with dual-voltage versions, or accept that you need a converter.

Then buy what you need before you fly, test it at home, and pack it in hand luggage so it is available on the flight and if your checked bag is delayed. Keep chargers and adapters together in one pouch so nothing is left behind at the hotel. If you are travelling with a group, agree who carries which adapter to avoid four universal adapters in one bag.

Finally, think about the return trip. Adapters are easy to leave in a socket, and the one you need at home may be the one you left abroad. A spare at home, or a note in your packing list, saves a purchase on arrival.