Plugs and voltage for visitors to the US
You need a Type A/B plug adapter. You almost certainly don't need a voltage converter — check each device's label for "100–240 V" and you'll find nearly everything qualifies. The exceptions are things that heat.
The socket you'll meet
US outlets are Type A (two flat parallel pins) and Type B (the same plus a round earth pin below). A Type B adapter fits both, so buy that one.
Mains supply is 120 volts at 60 Hz, against 220–240 V at 50 Hz across most of Europe, Asia, Africa and Australia.
Adapter versus converter — they are different things
This trips up a lot of people, and getting it wrong destroys equipment.
- A plug adapter changes the shape of the pins. It does nothing to the electricity.
- A voltage converter changes 120 V to 230 V, or the reverse.
Most travellers need only the adapter. The trick is knowing which of your devices needs more.
Read the label — this is the whole test
Every charger and appliance has its input printed on it, usually in tiny type on the plug body or the underside.
- "INPUT: 100–240 V, 50/60 Hz" → dual-voltage. Plug adapter only. This covers phone chargers, laptop chargers, camera chargers, electric toothbrushes and shavers.
- "INPUT: 220–240 V" only → single-voltage. Needs a converter, or leave it home.
When in doubt, don't guess. Plugging a 230 V-only device into 120 V usually just makes it feeble; the reverse destroys it.
What actually needs leaving behind
Things that turn electricity into heat are the usual single-voltage offenders:
- Hair dryers and straighteners
- Travel kettles and irons
- Some older electric shavers and curling tongs
Hotels supply hair dryers as standard. For an Airbnb, ask the host. Buying a cheap US hair dryer on arrival costs less than a converter capable of handling one.
The 60 Hz detail almost nobody needs
The US runs 60 Hz where much of the world runs 50 Hz. For anything electronic this is irrelevant — the power supply doesn't care.
It only matters for equipment with a mains-synchronised motor, such as some older turntables and mechanical clocks. Not a holiday problem.
Buy before you fly
Adapters are cheap online and expensive at airports and tourist shops. Get one with USB ports built in and you can charge two or three devices from a single US socket, which matters more than it sounds in a hotel room where the only reachable outlet is behind the nightstand.