What the standard defines
M.2 is a card and socket form factor published by PCI-SIG, used for solid-state drives and for wireless and other small add-in cards. It fixes the shape: the outline of the card, the edge connector, the notches cut into it and the mounting point that holds the far end down.
The four digits are a size code. The first two are the width in millimetres and the remainder is the length, so 2280 is a card 22 mm wide and 80 mm long. The rest of the family is the same width at other lengths — 2230, 2242, 2260 and 22110 among them — and 2280 is simply the size that became usual for a drive in a desktop or a full-size laptop.
The notches are keys, identified by letter, and they exist so that a card cannot be seated in a socket wired for something it does not speak. A card cut with one key and a card cut with two do not go into the same set of sockets.
And the socket’s electrical contract is a separate fact from its shape. A given M.2 socket may be wired for PCI Express lanes, for SATA, or for both, and the host’s documentation is where that is stated.
What it does not promise
It does not promise an interface. This is the whole of the point: 2280 is a measurement. An M.2 SATA drive and an M.2 NVMe drive are the same card outline and are not interchangeable in a socket wired for only one of them.
It does not promise a lane count. Sockets wired for PCI Express are commonly four lanes, but two-lane and single-lane sockets exist in compact machines and in some enclosures, and a four-lane drive in one of them trains down and works at the narrower width without complaint.
It does not promise a generation. The bus generation belongs to the host and the drive, not to the shape.
It does not promise the host takes an 80 mm card. Shorter sockets exist, and where the standoff is fitted and how much room lies in front of the connector decide what actually mounts.
And it does not promise a factory heatsink will clear. A drive with one is still a 2280 card, and still fouls a graphics card, a laptop lid or a drive tray that was designed around a bare one.
What it works alongside
Sockets wired for PCI Express take NVMe drives; sockets wired for SATA take M.2 SATA drives; sockets wired for both accept either and say so. Portable enclosures state which of the two they carry, and adapters exist that mount an M.2 card onto a full-height expansion card — useful when a machine has lanes to spare and no socket to put them in.
The questions that come up before an order
Will any 2280 drive fit any 2280 slot?
It will fit physically. Whether it works depends on what the socket is wired for — PCI Express, SATA, or both — and on the keying of the card edge. A host that accepts only one of the two buses says so in its manual, and that line is the one to find.
What do the other codes mean — 2230, 2242, 22110?
The same thing at other lengths. The first two digits are the width in millimetres and the rest is the length, so all of them are 22 mm wide and differ only in how far the card reaches. What a host accepts is set by where its standoff sits and how much room is in front of the socket.
Last reviewed 9 September 2026