An adapter changes the shape of the plug. A converter changes the voltage. They are completely different products and only one of them is in most people's bags. This is the confusion that destroys hair dryers, curling irons and travel kettles every summer, and it takes about ninety seconds to resolve permanently.
The thirty-second version
Different countries run on different mains voltage — broadly, around 110-120V in North America and Japan, and around 220-240V across most of Europe, Asia, Africa and Australia. They also use different physical plug shapes.
A travel adapter is a mechanical shape-shifter. It lets your plug fit the socket. It does absolutely nothing to the electricity flowing through it.
A voltage converter (or transformer) changes the electricity itself, stepping 240V down to 120V or vice versa. It's heavier, more expensive, and most travelers never need one.
How to know which you need: read the brick
Every charger and appliance has its input range printed on it, usually in tiny text on the plug or the power brick. Find the line that starts "INPUT". You'll see one of two things:
- "100-240V" — this is dual voltage. It handles anything in the world. You need only an adapter. Practically every phone charger, laptop charger, camera charger, e-reader and electric toothbrush made in the last fifteen years says this.
- "120V" only (or "220-240V" only) — this is single voltage. Plugging it into the wrong country's supply through a plain adapter will damage it, sometimes spectacularly. This is where a converter is required.
That's the whole test. If someone is travelling with a bag of USB chargers and a laptop, they need an adapter and nothing else.
The things that actually catch people out
The single-voltage survivors are almost all high-wattage heating appliances: hair dryers, straighteners, curling irons, travel kettles, some electric shavers and some medical devices. These are exactly the items people pack without thinking about, and exactly the ones that die.
Worse, they're also the items a cheap converter handles badly. High-wattage heating elements draw a lot of power, and many travel converters are rated only for low-wattage use or for short periods. Running a 1,800W hair dryer through an undersized converter is a good way to destroy both.
Our honest advice, and it's what experienced travelers do: don't take the hair dryer. Buy a dual-voltage travel version, or use the one in the hotel. Carrying a transformer around the world to run a hair dryer is a losing trade on weight alone.
Two more things adapters don't do
They don't add a ground. Many cheap adapters are two-pin only, which means an appliance that expects an earth connection won't get one. For phone chargers that's fine; for anything with a metal body it's worth using a grounded adapter.
They don't fix frequency. Mains frequency differs too (50Hz vs 60Hz). Modern electronics don't care. A small number of motor or clock-driven appliances do, and no adapter or standard converter addresses it.
What to actually buy
For essentially every traveler: a universal adapter with several USB ports. The USB ports are the real upgrade, because they let one object replace three separate chargers, which is the actual space saving in a bag. Look for a grounded version, and check it covers the specific region — "universal" usually means the four common plug types, which is enough for most itineraries.
We rank the options in our best universal travel adapters roundup, and an adapter appears on our travel gadgets list as one of the four items that earn their place for almost everyone.
One caution on the all-in-one blocks: they're heavy for what they are, and in a loose or worn socket a heavy adapter can sag and lose contact. A plug-kit style set is lighter but easier to lose a piece of. Both are reasonable; buy the block if they're going to one region, the kit if they're crossing several.
The bottom line
Buy an adapter. Read the word "INPUT" on anything with a heating element before it goes in the bag. If it says 100-240V you're done; if it says a single voltage, either leave it at home or buy the dual-voltage travel version of it. Almost nobody needs to own a converter, and the people who think they do usually need to buy a different hair dryer instead.
The check, in order
1. Read the INPUT line
On the plug or power brick. "100-240V" means an adapter is all that's needed. A single voltage means stop and think.
2. Identify the heating appliances
Hair dryers, straighteners, curling irons, kettles. These are the single-voltage survivors and the things that get destroyed.
3. Prefer replacing over converting
A dual-voltage travel hair dryer is lighter, cheaper and safer than carrying a transformer capable of running a normal one.
4. Buy grounded, with USB ports
The USB ports are the real space saving — one object instead of three chargers. A grounded adapter covers appliances with metal bodies.
5. Check the region
"Universal" usually means the four common plug types. That covers most itineraries, but confirm it against where they're actually going.
