Adapter vs Converter Calculator
The Adapter vs Converter Calculator checks your home country, destination country and your device's voltage rating together, then tells you plainly whether you need a plug adapter, a voltage converter, or both. Select both countries, choose whether your device is dual voltage or single voltage, and click Check My Device to get both answers side by side. Getting this backwards in either direction either risks a single-voltage device or has you lugging a converter you never needed. You may also want the voltage and plug compatibility checker.
Check Adapter vs Converter
Adapter, Converter, or Both — How This Calculator Decides
The calculator runs two independent checks. The first compares plug shapes between your home and destination countries — if they differ, you need an adapter. The second compares your device's declared voltage support against the destination's standard voltage — if your device is single voltage and the destination sits outside that voltage, you need a converter as well. A trip can need either, both, or neither.
How to Tell If Your Device Is Dual Voltage
Look at the small print on the charger, power brick, or the device's own rating plate for a line starting with "INPUT:". A range such as "100-240V ~ 50/60Hz" means the device is dual voltage and self-adjusts to whatever supply it's plugged into. A single figure, like "120V ~ 60Hz" with nothing else listed, means it's built for one voltage region only.
When You Need an Adapter Only
This is the most common outcome for modern electronics. Laptops, phone chargers, camera batteries and most USB power adapters are dual voltage by default, so once the plug physically fits — with an adapter if the shapes differ — the device handles the rest on its own. No converter, no extra weight in your bag. Next, check the Travel Adapter Calculator.
When You Need a Voltage Converter Too
Single-voltage, high-wattage devices are where a converter actually matters — think hair dryers, straighteners, and older appliances built for one region's mains supply. Running one outside its rated voltage without a converter is the scenario that damages the device or trips a breaker, so this is worth checking before you travel, not after you've plugged in.
Step-Down Converters
A step-down converter lowers a higher supply voltage to match a device built for a lower one — the case for a 120V-only device travelling into a 220-240V country.
Step-Up Converters
A step-up converter does the opposite, raising a lower supply voltage for a device built for a higher one — less common for travelers, but relevant for a 230V-only appliance used somewhere on the 100-127V band.
| Device voltage rating | Destination supply | Converter direction |
|---|---|---|
| 120V only | 220-240V | Step-down |
| 230V only | 100-127V | Step-up |
| 100-240V (dual voltage) | Any | Not needed |
What happens if I use a single-voltage 120V device on a 230V supply without a converter?
Running a single-voltage 120V device on a 230V supply without a converter typically damages it immediately — the higher voltage overloads components built for half that level. It can also trip the destination's circuit or, in the worst case, create a fire risk, so this isn't a situation worth testing.
Do dual-voltage devices ever still need a converter?
No — if the label genuinely shows a range like 100-240V, the device's own power supply handles the conversion internally, and adding an external converter is unnecessary and sometimes counterproductive. The only thing a dual-voltage device needs abroad is the correct plug adapter.
Are voltage converters and transformers the same thing?
They're closely related — a transformer is the core component that steps voltage up or down, and most travel voltage converters are transformers packaged for this purpose. Converters are usually sized for continuous use with electronics; heavier-duty transformers are built for appliances that draw far more power, like hair dryers or irons.
Does a converter also solve the plug shape problem?
No — a voltage converter only changes the electricity, not the pin shape, so you'll typically still need a separate plug adapter to physically connect the converter, or the device, to the destination's socket.
What wattage rating do I need on a voltage converter?
Buy for more than your device's rated wattage, not just enough to cover it — running a converter close to its maximum continuous wattage for long periods is what causes overheating. If you're not sure of your device's wattage, a travel power wattage calculator works out the current draw so you can size a converter with real headroom.