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M.2 EXPANSION · FAQ

What M.2 form factor sizes are available?

M.2 modules come in eight defined lengths and four widths, encoded in a four-digit size code (2280, 22110, etc.). Here's what the codes mean and which sizes to expect on industrial platforms.

01

The short answer

M.2 module size is encoded in a four-digit number: the first two digits are the width in millimeters, the last two are the length. A 2280 module is 22 mm wide and 80 mm long. A 22110 module is 22 mm wide and 110 mm long. The standard defines several widths and lengths, but the dominant size on industrial platforms is 2280.

02

The width codes

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    22 mm wide. The dominant width across industrial M.2 modules. SSDs, wireless cards, AI accelerators, video capture cards — almost all are 22 mm. Host sockets are almost always 22 mm wide.
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    30 mm wide. Used for some 5G cellular modems where the wider footprint accommodates antenna routing and component layout. Hosts with 30 mm slots are a minority.
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    12 mm and 16 mm wide. Defined in the standard but rare in practice. Reserved for ultra-compact applications like wearables and IoT sensors. Not typically seen in industrial computing.
03

The length codes

Eight lengths are defined: 16, 26, 30, 38, 42, 60, 80, and 110 mm. Five of these dominate industrial use:

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    2230.0 Compact. Used for cellular modems and some Wi-Fi modules where board space is tight.
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    2242.0 Mid-length. Common for SATA SSDs in compact systems and some cellular modules.
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    2260.0 Less common transitional length. Found on some industrial SSDs sized between 2242 and 2280.
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    2280.0 The dominant size. The default for NVMe SSDs, most M.2 AI accelerators, and the standard size every host platform supports.
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    22110.0 Extended length. Used for industrial SSDs that need extra board space for higher-capacity NAND, additional power-loss protection capacitors, or thermal management hardware. Often found in long-deployment industrial systems.
04

Host socket compatibility

Most industrial M.2 sockets support multiple lengths via repositionable mounting screws. A motherboard advertising a 2280 slot will typically also accept 2242 and 2260 modules — the standoff screw moves to the appropriate position for the shorter module.

The reverse is not true: a 22110 module will not fit a 2280-only slot. Check the maximum supported length on the host platform’s datasheet before ordering longer modules.

The keying still applies regardless of length (see What is M.2 keying?) — a 2280 NVMe SSD is M-keyed and won’t fit a B-key cellular modem socket even though the lengths happen to match.

For the full M.2 specification — keys, bus interfaces, applications — see our M.2 expansion slots white paper.