Short answer: every USB-C cable has the same plug, but inside they differ in three separate ways. They differ in how much current they carry (3 A, about 60 W, by default; 5 A with an electronic marker chip for 100 W or 240 W), how fast they move data (from USB 2.0 at 480 Mbps up to 80 Gbps), and whether they can carry video at all. Power and data are rated independently, so a 240 W cable can still be a slow USB 2.0 cable.
Our chargers-and-cables guide covers the basic 60 W versus 100 W rule. This guide explains what sits behind it and how to tell which cable is in your drawer.
Power: 60 W, 100 W and 240 W
The USB Type-C specification rates standard cables for 3 A. It allows cables designed for USB Power Delivery, and identified by electronic marking, to carry up to 5 A. At the 20 V used by most laptops, that is the difference between 60 W and 100 W.
USB PD 3.1 then raised the ceiling to 240 W by adding 28 V, 36 V and 48 V steps, and the USB Type-C specification was updated to define 240 W cable requirements. In practice you will see three power classes: 60 W, 100 W (older 5 A cables) and 240 W. The current release of the specification (2.5, March 2026) deprecates the 100 W-only 5 A cables in favour of 240 W ones.
Google's own 67 W charger page shows what happens with the wrong cable: a device that needs more than 60 W must use an e-marked cable certified above 60 W, otherwise it still charges but at up to 60 W.
The e-marker: the chip you cannot see
The specification says every full-featured USB-C cable is electronically marked, USB 2.0 cables may be, and any cable rated above 3 A is. The e-marker is a small chip in the plug that tells the charger and device what the cable can handle. Without one, the cable counts as a standard 3 A cable.
That is why the cable matters for some phones too. Samsung's 45 W Super Fast Charging 2.0 is rated with a 5 A cable on models before the Galaxy S25, and Samsung warns that off-spec, high-resistance cables can make charging stop intermittently.
Data: from 480 Mbps to 80 Gbps
USB-IF now asks makers to describe speed in plain numbers: USB 5Gbps, 10Gbps, 20Gbps, 40Gbps and 80Gbps. Version names such as USB 3.2 or USB4 are not meant for consumer packaging, though you will still see them; Apple, for example, describes USB 3.2 Gen 2 as up to 10 Gbps. Thunderbolt sits on top: Intel describes Thunderbolt 4 as 40 Gbps, for laptops that charge at up to 100 W, and Thunderbolt 5 as 80 Gbps, with Bandwidth Boost up to 120 Gbps and charging up to 240 W on some devices. Apple's Thunderbolt 4 Pro Cable delivers up to 100 W and its Thunderbolt 5 Pro Cable up to 240 W.