Type B vs Type M Plugs: Differences & Compatibility

Type B vs Type M plugs are not compatible: an adapter is needed in both directions. Type B is a 3-pin, grounded plug rated 15A at 100-127V, while Type M is a 3-pin, grounded plug rated 15A at 220-240V. The two differ mainly in voltage and pin design, which is what decides compatibility — whether a Type B plug fits a Type M socket, and vice versa. Next, check will a type J plug work in a type N socket without an adapter.

Swipe to compare

Not Compatible Adapter needed in both directions Compatible Adapters	Type B	Type M
Standard	NEMA 5-15	BS 546 (15A)
Pin Configuration	Two flat parallel pins plus round grounding pin (4.8mm diameter)	Three large round pins in triangular pattern (earth 8.7mm diameter, live/neutral 7.1mm diameter)
Grounding	Grounded	Grounded
Pin Count	3	3
Amperage	15A	15A
Voltage Range	100-127V	220-240V

Key Differences Between Type B and Type M

Here's how Type B and Type M compare, point by point.

Grounding: Both Type B and Type M are grounded.
Pin Size and Shape: Type B: Two flat parallel pins plus round grounding pin (4.8mm diameter). Type M: Three large round pins in triangular pattern (earth 8.7mm diameter, live/neutral 7.1mm diameter).
Application: Type B is typically used for heavy-duty appliances such as hair dryers, kettles, and heaters. Type M is typically used for heavy-duty appliances such as hair dryers, kettles, and heaters.

Type B and Type M Compatibility

Type B in Type M Sockets: Generally no. A Type B plug (Two flat parallel pins plus round grounding pin (4.8mm diameter)) does not fit a Type M socket (Three large round pins in triangular pattern (earth 8.7mm diameter, live/neutral 7.1mm diameter)) without a travel adapter.

Type M in Type B Sockets: Generally no. A Type M plug (Three large round pins in triangular pattern (earth 8.7mm diameter, live/neutral 7.1mm diameter)) does not fit a Type B socket (Two flat parallel pins plus round grounding pin (4.8mm diameter)) without a travel adapter.

If you're planning a trip, tell us which country you're visiting and we can confirm whether you need a Type B or Type M travel adapter.

Type B vs Type M plug comparison: Type B and Type M wall sockets and plugs side by side, with the verdict and which way each plug fits, a specification table, key differences and how to tell them apart. Verdict: Not Compatible. — Type B vs Type M Plug: Differences and Compatibility (Infographic)

Does a Type B plug fit into a Type M socket?

Generally no. A Type B plug (Two flat parallel pins plus round grounding pin (4.8mm diameter)) does not fit a Type M socket (Three large round pins in triangular pattern (earth 8.7mm diameter, live/neutral 7.1mm diameter)) without a travel adapter. Compare this with type H vs type L socket.

Are Type B and Type M plugs the same?

No. Type B follows the NEMA 5-15 standard and Type M follows BS 546 (15A) — they differ in voltage rating.

Which countries use Type B and Type M plugs?

Type B plugs are used in 54 countries, including United States of America, Japan, Vietnam, Thailand, Canada. Type M plugs are used in 9 countries, including India, South Africa, Nepal, Namibia, Mozambique.

How can you tell a Type B plug from a Type M plug?

A Type B plug has two flat parallel pins plus round grounding pin (4.8mm diameter), and is grounded. A Type M plug has three large round pins in triangular pattern (earth 8.7mm diameter, live/neutral 7.1mm diameter), and is grounded. The quickest tell is pin size and spacing — compare the two pin configurations above. You might also want how do i tell a type D plug apart from a type N plug.