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What the ranking means

Type C is not really a socket standard. It appears at the top because the Europlug is accepted by every European socket family — French E, German F, Swiss J, Danish K, Italian L and Brazilian N — so most of Europe counts twice. If you are carrying chargers, Type C compatibility is the single most useful thing to have.

Type F is the real European default. Schuko covers Germany, the Netherlands, Spain, Portugal, Scandinavia, Poland, Russia, Korea and much of Africa and Central Asia. Where a country has both C and F listed, the F socket is the earthed one and the C plug still fits it.

Type A and B are a package deal. North America, Central America and Japan use the flat-blade family, with B providing earth. Type B sockets accept A plugs, which is why the two counts stay close.

Type G is the most geographically scattered. Britain, Ireland, Cyprus, Malta, the Gulf, Malaysia, Singapore, Hong Kong, Kenya and Nigeria — the shape followed the British wiring trade. It is also the least compatible: nothing else fits it without an adapter.

The rarest types are national standards. Type H (Israel), Type J (Switzerland), Type K (Denmark), Type N (Brazil, South Africa) and Type O (Thailand) exist because each country designed for itself and never had a reason to switch.

What this means in practice

A universal adapter covers Type A, C, G and I pins, which handles most of the world. It will not help with South Africa’s Type M, Brazil’s Type N or India’s Type D in older buildings — for those you want a dedicated adapter, or a locally bought one at the airport.