Plug Type and Voltage by Country

In short There are fifteen mains plug types in use worldwide, lettered A to O by the IEC, and two voltage bands: roughly 100–127 V, used across the Americas and Japan, and roughly 220–240 V, used almost everywhere else. The two bands are not arbitrary — they descend from separate electrification histories, which is also why the low band runs at 60 Hz and the high band mostly at 50 Hz. Knowing a country's plug letter tells you what adapter to buy; knowing its voltage tells you whether an adapter is enough. Those are different questions and the second one is the one that costs money. A few countries are worth knowing about specifically. Japan is the only country with two mains frequencies, 50 Hz in the east and 60 Hz in the west, and at 100 V it has the lowest mains voltage anywhere. Brazil runs 127 V and 220 V in different regions with identical sockets. The Philippines, Peru, Cuba, China, Thailand, Vietnam, Saudi Arabia and the Maldives all carry 220 V or more on sockets that accept flat American pins, which means a US appliance fits and dies. And the Maldives accepts more plug types than anywhere on earth, because its resorts were built by contractors from wherever the funding came from.