What does 100–240V on your charger actually mean?

That small print on your charger is the most important thing to check before travelling internationally. Here's exactly what it means. Published July 2026 · By PlugsRus.net 100–240V means your charger is dual-voltage and will work anywhere in the world with only a plug adapter. It accepts the full range of international voltages — from Japan's 100V up to Europe's 240V — without any additional converter.

Where to find the label

Look on the charger body itself — not the cable, not the plug, but the actual brick or block that plugs into the wall. The voltage rating is usually printed in small text alongside the input and output specifications. It often looks something like this:

INPUT: 100–240V ~ 50/60Hz 0.5A
OUTPUT: 5V ⎓ 2A

The INPUT line is what you're looking for. Everything after that describes what the charger delivers to your device, which isn't relevant to international travel safety.

What the numbers actually mean

Voltage is the electrical pressure in the wall socket. Different countries use different standards:

  • 100V — Japan (the lowest in the world)
  • 110–120V — North America (USA, Canada, Mexico)
  • 220–240V — UK, Europe, Australia, India, China, most of Asia, Africa, and South America

A charger rated 100–240V contains internal circuitry — a switched-mode power supply — that automatically detects the incoming voltage and adjusts itself. Plug it into a 100V Japanese socket or a 240V British socket and it handles both without any intervention from you.

A charger rated 120V only has no such circuitry. It expects exactly 120V. Connect it to 230V and it receives roughly double its rated voltage. The result is immediate overheating, component failure, and in some cases fire or a burned-out socket.

What's almost always dual-voltage (100–240V)

The good news: the devices most travellers carry are almost universally dual-voltage. Modern electronics are designed for global markets and manufacturers build in dual-voltage support as standard.

  • Smartphone chargers — iPhones, Android phones, all modern brands
  • Laptop power bricks — MacBooks, Windows laptops, Chromebooks
  • Tablet chargers — iPads, Samsung tablets, Kindles
  • USB-C chargers and GaN chargers — virtually all are dual-voltage by design
  • Camera battery chargers — Canon, Nikon, Sony, Fujifilm all ship dual-voltage chargers
  • Wireless earphone charging cases — AirPods, Sony WH-1000XM, Bose
  • Electric toothbrush chargers — most Oral-B and Philips Sonicare chargers are dual-voltage

For all of the above, check the label to confirm — but you will almost certainly see 100–240V. These devices need only a plug adapter abroad, not a voltage converter.

What's often NOT dual-voltage

Some categories of appliances are commonly sold as single-voltage, particularly in North America where the 120V standard has been in place for over a century. Manufacturers serving that market don't always invest in dual-voltage circuitry for lower-cost products.

  • Hair dryers — the most common travel casualty. Most North American hair dryers are 120V only unless specifically labelled as "dual voltage" or "travel"
  • Curling irons and straighteners — same situation. Travel or professional versions are often dual-voltage; standard consumer models often are not
  • Electric shavers — budget models are frequently 120V only; many mid-range and premium shavers are dual-voltage. Check carefully
  • Clothing steamers — nearly always single-voltage
  • Travel kettles — sold in voltage-specific versions; always check
  • Baby bottle sterilisers and warmers — usually single-voltage
Rule of thumb: anything with a heating element or a motor is more likely to be single-voltage. Anything that's purely electronic — chargers, power banks, audio devices — is more likely to be dual-voltage.

What about the Hz (frequency) rating?

You'll also see a frequency rating on the label — typically 50/60Hz for dual-voltage devices. Frequency refers to how many times per second the electrical current alternates direction. North America uses 60Hz; most of the world uses 50Hz.

For electronics with switching power supplies (phones, laptops, most chargers), frequency makes no practical difference. The device handles both 50Hz and 60Hz transparently.

For devices with motors — fans, some older clocks, certain kitchen appliances — a frequency mismatch can cause the motor to run slightly slower or faster than designed. This is rarely damaging but worth knowing. Most modern appliances with motors are designed to handle both frequencies.

The five-second check before every trip

Before packing any appliance for international travel, flip it over and read the input label. The decision tree is simple:

  1. Does it say 100–240V? → Pack it with a plug adapter. You're done.
  2. Does it say 120V only or just 120V? → You need a voltage converter, or leave it at home.
  3. Can't find or read the label? → Assume it's single-voltage. Don't risk it.

This check takes five seconds and has saved more than a few fried appliances — and more importantly, it avoids the much more serious risk of an electrical fire in a hotel room.

If you need a converter

For US devices used abroad (120V appliances in 220–240V countries), the 220V to 110V Step-Down Converter covers 80+ countries with PD fast charging built in.

View step-down converter on Amazon →

For foreign devices used in the US (220–240V appliances in a 110–120V country), the 2000W Step-Up Transformer handles most home appliances safely.

View step-up transformer on Amazon →

As an Amazon Associate we earn from qualifying purchases.

Related reading

This article is general travel information, not electrical or safety advice. Always check device labels and consult the manufacturer for medical equipment or high-wattage appliances. Data aligned with the IEC World Plugs reference.