Quick answer
US plugs do not fit UK sockets, so you need a UK plug adapter for plug type G. In the UK, the declared low-voltage mains supply is 230 volts at 50 hertz. An adapter only changes the plug shape, so check that each device accepts 230 V before you pack it.
Checked on 11 November 2026 against legislation.gov.uk (Electricity Safety, Quality and Continuity Regulations, regulation 27).
- Declared frequency: 50 Hz.
- An adapter does not convert voltage. A device must accept 230 V, or you need a voltage converter.
- A type G adapter should contain a fuse. The UK government has published safety reports on adapters without one.
On this page
UK power supply: the key data
These values come from UK electricity supply law.
| Item | UK value | What it means for you |
|---|---|---|
| Plug and socket | Type G | US plugs need an adapter. |
| Declared voltage (low voltage) | 230 V | Your device label must include 230 V. |
| Declared frequency | 50 Hz | Your device label should include 50 Hz. |
| Permitted voltage variation | +10% / −6% | The supply can be slightly above or below 230 V. |
| Permitted frequency variation | ±1% | The frequency stays very close to 50 Hz. |
| Adapter marking | 13A / 250V | This marking alone does not prove the adapter has a fuse. |
Plan for 230 V at 50 Hz across the UK.
Adapter or converter: what each device needs
A UK travel adapter lets a US plug fit a UK socket. It does not change the voltage. Before you pack a device, read the input line on its charger or label.
| What the label shows | What you need |
|---|---|
| An input range that includes 230 V and 50 Hz | A type G adapter only |
| A single voltage that is not 230 V | A voltage converter as well as an adapter, or leave the device at home |
| A voltage switch | Set it to the 230 V position, then use an adapter |
| No clear voltage information | Do not plug it in until you can confirm the rating |
How to choose a safe UK travel plug adapter
UK government product safety reports describe unsafe type G travel adapters. Use them as a checklist when you buy a US to UK plug adapter.
- Check that it has a fuse. One unbranded type G adaptor was marked 13A / 250V, which suggests a fuse, but it had none. The government rated it a serious risk of electric shock.
- Check that it names a maker or importer. The same unbranded adaptor showed no manufacturer or importer and lacked the required markings.
- Check that the pins fit properly. Travel adaptors recalled after sale through TK Maxx had pins outside the dimensional requirements. It was also possible to insert only one pin.
- Check for recalls. The TK Maxx adaptors also failed an electric strength test and posed a risk of electric shock. You can search the product safety reports on gov.uk.
What to pack
- A type G adapter for each device you want to charge at the same time.
- Chargers whose labels include 230 V and 50 Hz.
- A voltage converter only if you must bring a device that does not accept 230 V.
- Your passport and, if you need one, your ETA details, kept separate from your electronics.
Documents and entry
An ETA is a digital permission to travel for nationals who do not need a visa for the UK. It is not a visa, and Border Force still decides on entry when you arrive. Since 25 February 2026, the ETA rule has been strictly enforced, and carriers should not let you board without one if you need it. Each traveller who needs an ETA, including babies and children, needs their own passport and their own ETA, which costs £20.
To check whether this applies to you, see Do I need a UK ETA? and UK ETA for US citizens: requirements, cost and how to apply. The step-by-step guide explains how to apply for a UK ETA. To plan your timing, see UK ETA processing time and UK ETA cost and validity.
FAQ
Do I need a voltage converter in the UK?
Only for a device that does not accept 230 V. If the label shows an input range that includes 230 V and 50 Hz, a type G adapter is enough.
Does a UK plug adapter change the voltage?
No. An adapter only changes the plug shape so that a US plug fits a type G socket. The socket still supplies 230 V at 50 Hz.
Do I need flight or hotel details to apply for an ETA?
No. The ETA application does not ask for travel details such as flights, accommodation or dates. See how to apply for a UK ETA.
Sources
- legislation.gov.uk: The Electricity Safety, Quality and Continuity Regulations, regulation 27
- GOV.UK: Product safety report, unbranded type G travel adaptor 13A/250V
- GOV.UK: Product recall, global travel adaptors sold via TK Maxx
This guide is general information, not legal or immigration advice. BritainEntry is an independent website and is not connected with the UK government.