Travel power guide
Adapter vs Converter: What's the Difference?
Direct answer
Adapter vs Converter: What's the Difference?
A plug adapter changes the shape of your plug so it fits a foreign socket; a voltage converter changes the voltage so a device built for one voltage can run on another.
Updated 2026-09-04
You almost always need an adapter; you only need a converter for single-voltage devices used in a country with a different voltage.
A plug adapter is a passive shell: it lets your plug's pins physically connect to a differently-shaped socket. It does not touch voltage, frequency, or power.
A voltage converter (or transformer) steps voltage up or down — for example 230V down to 120V — so a single-voltage device receives the voltage it expects. It is heavier, pricier, and rated by a wattage you must not exceed.
To tell which you need, read the INPUT line on your device label. "100–240V" means dual voltage — an adapter is enough. A single value like "120V" means single voltage — you need a converter, or a dual-voltage replacement.
The fastest test is plug shape first, voltage second. If the plug shape is different but the label says 100–240V, buy only a plug adapter. If the label shows a single voltage and the destination voltage differs, solve voltage before you think about plug shape.
Converter sizing is a separate safety step. A 60W shaver charger and a 1500W hair dryer are not in the same category, even if both say 120V. Small electronics can sometimes be sized with headroom; high-watt heating appliances should usually be replaced with a dual-voltage travel model or bought locally.
For multi-country trips, the cleanest workflow is: list every device, mark each voltage label, then choose adapters for the destination sockets. That prevents the common mistake of buying one universal adapter and assuming it also fixes voltage.
A quick example: a US Type A phone charger labeled 100–240V can use a simple plug adapter in Germany; a US Type A hair dryer labeled 120V cannot. Same home plug shape, different voltage risk.
The 30-second decision
Three questions settle almost every case. First: what does the INPUT line on your device say? Second: what voltage does the destination use (every country page on this site states it)? Third: what socket shape does the destination use?
If the printed range covers the destination voltage, buy only a plug adapter for the socket shape. If it does not, a correctly sized voltage converter is the minimum — and for high-watt heating devices, the honest answer is usually a dual-voltage travel version or buying one at the destination instead.
Six trips, six verdicts
US phone charger (100-240V) to Germany: plug adapter only. The charger handles 230V by design; the Type C/F socket is the only obstacle.
US hair dryer (120V, 1500W+) to France: do not plug it in, with or without an adapter. A converter for that wattage is heavy and runs hot; a dual-voltage travel dryer or a hotel dryer is the safe route.
European shaver charger (230V only) to the United States: it needs a step-up converter — or skip the gear, since dual-voltage replacements are small and cheap.
UK laptop (100-240V, Type G plug) to the United States: plug adapter only. The big Type G plug needs a shape change; the power brick itself is world-ready.
US CPAP machine to Japan: the supplied power bricks are often rated 100-240V, but the only proof is the label on your unit — the verdict for label-dependent devices is always "check the label", not an assumption.
US curling iron (120V) to Australia: same story as the hair dryer — a heating element on a 230V grid is the highest-risk combination this site tracks. Replace it, don't convert it.
Transformer vs electronic travel converter
A transformer-based product still needs explicit compatibility with the appliance, supply frequency, duty cycle and startup demand. Physical size and a wattage margin alone are insufficient.
A compact "travel converter" is usually an electronic voltage reducer designed for short sessions with simple resistive heat devices, and manufacturer manuals commonly exclude electronics outright. Follow the converter's own manual over any general rule, including this one.
Either way, the rating must exceed the device's wattage with headroom — PlugVoltage's sizing tool applies a preliminary 25% arithmetic margin, not a safety certification — and one converter powers one device at a time.
When neither is the answer
For a 1500W dryer or kettle on the wrong voltage, the math stops making sense: a converter that size is bulkier than the appliance. That is why every high-watt heating device on a mismatched grid gets a do-not-plug-in verdict here rather than a shopping link for a converter.
Options to check with the manufacturer or accommodation: a dual-voltage version of the same tool, the hotel's own appliance, or a cheap local purchase at the destination.
What the evidence covers
A source supports only the facts, socket types or models listed below. A model example does not verify every device in its category. Confirm your own label and outlet.
- SKROSS: Can adapters convert voltage? · checked: 2026-09-04
A passive plug adapter changes the connection, not the mains voltage. Check the device nameplate. Answer paragraphs 1–2. Manufacturer guidance for its adapters; this does not approve a voltage converter for a particular appliance.
- SKROSS: World to USB series manual, version 1.2 · checked: 2026-09-04
AC current limits and USB output are separate. In the AC20PD examples a single USB-C port reaches about 20W; simultaneous USB-A + USB-C use shares 15W. PDF page 1, English technical ratings and safety instructions. These figures apply to the named series. The manual prohibits stacking adapters and multiplug sockets; other models require their own manual.
- Apple: MacBook Pro USB-C power adapter specifications · checked: 2026-08-21
Apple lists 100–240V AC, 50–60Hz for the named 70W, 96W and 140W USB-C power adapters. Power adapter specifications. A checked manufacturer family example; not proof for every USB, GaN or laptop charger.
- Conair: 1875 W Model 303 hair dryer instructions · checked: 2026-08-21
Conair Model 303 specifies 110–125V AC, 60Hz and prohibits use with a voltage converter. PDF page 1, important safety and operating instructions. This label excludes Japan’s 100V. It does not describe every hair dryer.
- ResMed: AirSense 11 user guide · checked: 2026-08-21
The AirSense 11 65W supply specifies 100–240V, 50–60Hz; typical and peak consumption differ. Technical specifications, printed page 22 (PDF page 25). Only the named supply and machine are covered. Confirm your own supply, accessories and manufacturer instructions.
Adapter or converter examples
The safest answer comes from checking plug shape and voltage as separate decisions.
Label examples to recognize
Use these text patterns as visual cues before you trust a charger, hair tool, or adapter abroad.
Adapter markings to check
A good adapter makes socket coverage and limits explicit without pretending to convert voltage.
Adapter vs converter comparison
| Question | Plug adapter | Voltage converter |
|---|---|---|
| Changes plug shape? | Yes | No, not by itself |
| Changes voltage? | No | Yes, step-up or step-down |
| Needed for dual-voltage chargers? | Usually yes | No |
| Rated by watts? | Only for current limit | Yes — must exceed device watts with headroom |
| Safe for hair dryers/kettles? | Only if the device is dual-voltage | Usually no for high-watt heating gear |
Step by step
- Find the INPUT line on your device, plug, or power brick.
- Read the voltage range. "100–240V" means dual voltage.
- If it reads 100–240V, a plug adapter is enough. If it shows a single value like "120V", you need a voltage converter — or a dual-voltage replacement.
Frequently asked questions
Do I need an adapter or a converter for Europe?
Check your device label first. "100-240V" devices — most chargers — need only a plug adapter for European Type C/E/F sockets. Single-voltage 120V devices need a converter, and high-watt heating tools are better replaced with dual-voltage versions.
Can a plug adapter change voltage?
No. A plug adapter is a passive shape-changer: your device receives exactly the destination's voltage through it. Anything that claims to change voltage is a converter, which is different equipment.
Will a converter make my hair dryer safe in Europe?
Usually not in practice. A 1500W+ dryer needs a converter rated far above what compact travel units deliver, and such units are meant for short, attended use at best. A dual-voltage travel dryer is the reliable answer.
Do universal travel adapters convert voltage?
No — despite the name, universal adapters only cover many socket shapes. Unless a product explicitly markets a built-in transformer and states an output voltage and wattage, assume it does not convert.
Are adapters with USB ports converters?
Only for the USB side, and only when the adapter itself is rated 100-240V — nearly all reputable travel adapters are, but its printed input is the proof. The USB ports contain their own small power supply that outputs low-voltage DC; the AC socket passthrough remains unconverted mains voltage.
What happens if I use only an adapter with a 120V device on 230V?
The device receives roughly double its design voltage, which can overheat or destroy it. See the dedicated guide on plugging 110V devices into 220V grids for the failure modes.
How many watts can a plug adapter handle?
Look for the printed current limit, commonly "MAX 10A 250V~". That is a load ceiling for the adapter's contacts, not voltage conversion — and high-watt heating devices can approach it quickly.
Related guides
Guidance only — not professional electrical advice. Always confirm against your device's label before plugging in. Local wiring (especially in hotels and older buildings) can vary.