HomeJapan → US
Do I need an adapter from Japan to the US?
No adapter needed for phone or laptop in the United States.
Japan: Type A/B, 100 V, 50 / 60 Hz → United States: Type A/B, 120 V, 60 Hz.
Dual voltage (100–240 V input) covers 120 V. Your Type A plug fits the United States' Type B sockets.
Dual voltage (100–240 V input) covers 120 V. Your Type A plug fits the United States' Type B sockets.
120 V is within what this device expects. At 120 V instead of 100 V it runs above its rating; check the label before using it for long. Your Type A plug fits the United States' Type B sockets.
120 V is in the same range as at home, so it works whether or not it is dual voltage. Your Type A plug fits the United States' Type B sockets.
120 V is in the same range as at home, so it works whether or not it is dual voltage. Your Type A plug fits the United States' Type B sockets.
120 V is within what this device expects. At 120 V instead of 100 V it runs above its rating; check the label before using it for long. Your Type A plug fits the United States' Type B sockets.
Why
Plug shape. Japan uses Type A (two flat parallel pins) and Type B (two flat parallel pins and a round earth pin). Sockets in the US are Type A (two flat parallel pins) and Type B (two flat parallel pins and a round earth pin). They are compatible, so no adapter is needed.
Voltage. Japan is 100 V; the US is 120 V. Same voltage family, so everything you own will run. Adapter or converter?
Frequency. Japan is 50 / 60 Hz; the US is 60 Hz. No change to worry about.
Japan: Japan runs on 100 V nationwide, lower than anywhere else. The frequency is split: 50 Hz in eastern Japan (Tokyo, Yokohama, Sapporo, Sendai) and 60 Hz in western Japan (Osaka, Kyoto, Nagoya, Hiroshima, Fukuoka). Sockets are mostly ungrounded Type A; grounded Type B sockets are uncommon outside newer buildings, so a US three-pin plug may need a 3-to-2 adapter. Japanese Type A pins are the same width, so a polarised US plug (one wide blade) may not fit an older Japanese socket.
Frequently asked questions
Do I need an adapter from Japan to the US?
No, not for a phone or laptop: your Type A plug fits the United States' Type B sockets.
Do I need a voltage converter from Japan to the US?
No. Both are in the same voltage range (100 V and 120 V), so single-voltage appliances work. A hair dryer will run differently, though: at 120 V instead of 100 V it runs above its rating; check the label before using it for long.
Will my Japanese phone charger work in the US?
Yes. Phone and laptop chargers are dual voltage (100–240 V). You do not even need an adapter.
What about the reverse trip, the US to Japan?
No adapter needed for your devices in Japan. Full US to Japan guide.