A Certified USB-C Cable’s Logo Gives Its Speed and Watts

The logo on a certified USB-C cable states two things: its data rate (5, 20, 40 or 80Gbps) and its power rating (60W or 240W). A logo with only a wattage, and no Gbps figure, marks a USB 2.0 cable that carries data at up to 480Mbps.

USB-IF, the industry body behind USB, allows these logos only on cables that have passed its compliance testing. Under its current guidelines, every USB-C to USB-C cable that passes must carry one, embossed or printed on the plug, so a new cable without one has not been certified.

What each logo means

USB-IF’s cable guidelines define 10 logos. Eight combine a data rate with a power rating; two give power only.

Logo on the plug	Data	Power	What it tells you
USB 80Gbps · 240W or 60W	80Gbps	240W or 60W, as printed	The top USB data rate
USB 40Gbps · 240W or 60W	40Gbps	240W or 60W	USB-IF’s 2022 USB 80Gbps announcement says 80Gbps also runs over existing 40Gbps passive cables
USB 20Gbps · 240W or 60W	20Gbps	240W or 60W	A cable at 20V and 3A gets the 60W version, per USB-IF’s own example
USB 5Gbps · 240W or 60W	5Gbps	240W or 60W	The lowest certified data rate above USB 2.0
240W, no data rate	480Mbps (USB 2.0)	240W	A charging cable: no USB 3.2, USB4 or Alt Mode
60W, no data rate	480Mbps (USB 2.0)	60W	The same, with charging up to 60W
No logo	Not certified	Not certified	Whatever the maker claims, unverified by USB-IF

The 60W rating matches USB-IF’s example of a cable that “supports 20V at 3A”. 240W is the ceiling of USB Power Delivery 3.1, reached at 48V. Before revision 3.1, USB PD stopped at 100W, using 20V over cables rated at 5A.

The cable guidelines contain no 10Gbps cable logo, although USB-IF does give ports and devices a “USB 10Gbps” name. USB-IF does not explain the gap.

The trap is the wattage-only logo

A cable sold as “240W” sounds like the top model. If the plug shows 240W and no Gbps figure, it is a USB 2.0 Type-C cable. USB-IF says such cables “deliver data at up to 480Mbps”, that this “is not reflected in this logo”, and that they support neither USB 3.2, USB4 nor Alt Mode.

Without Alt Mode there is no video, which is one reason a hub may not drive a monitor; the cable is not the only one, as what decides whether a USB-C hub runs two monitors explains.

That cable charges a laptop at full power and copies files to a fast SSD at USB 2.0 speed. USB-IF’s own language guide says a USB 3.2 or USB4 device used with a USB 2.0 cable “will perform at the slower USB 2.0 speed”. The charging side of that pairing, and why wattage alone does not predict charging speed, is in why a 65W charger often charges below 65W.

What a cable without a logo promises

Nothing that USB-IF stands behind. Its licence page says the logos “may be used only” with products that passed compliance testing and are on its Integrators List, and its cable guidelines say every USB-C to USB-C cable must carry a data-rate and power logo to pass. USB-IF’s documents describe what certified cables do; they do not describe uncertified ones.

Three things USB-IF does say narrow what an unlabelled cable’s packaging can mean:

• “USB-C” names the connector, not a speed. USB-IF: “USB Type-C is not USB 3.2 or USB4”, and it “is not USB Power Delivery”. A cable can be USB-C and do any of those, or none.
• Old specification names are not meant for shoppers. “USB4 Version 2.0”, “USB 3.2” and “SuperSpeed Plus” are, in USB-IF’s words, “not intended to be used in product names”. The names it recommends are USB 80Gbps, 40Gbps, 20Gbps, 10Gbps and 5Gbps.
• Retailers carry responsibility too. USB-IF says online retailers are “responsible for ensuring” products sold under the USB-C trademarks comply with the specification, and points them to its public product search.

USB-IF says vendors must state the data rate in packaging and advertising, and recommends wording such as “signals at 40Gbps” or “supports USB 40Gbps”. On an uncertified cable that is the maker’s statement, not a tested one.

HDMI’s certification body also names its cables by bandwidth, and bans version numbers on cable packaging; which HDMI cable a TV or console needs covers that label.

How to check before buying

1. Read the plug. Certified logos sit on the overmold, the plastic around the connector.
2. Read the packaging logo. USB-IF’s packaging logos include the word “CERTIFIED”, and its guidelines forbid using them without it.
3. Search the list. USB-IF’s product search covers only products certified to bear its logo. It shows the last two years by default, and USB-IF warns that products certified earlier “may fail the current iteration” of its compliance programme.
4. Match the whole chain. USB-IF says full USB 3.2 or USB4 speed needs the computer, the device and a full-featured USB-C cable all to support it.

Where Thunderbolt cables fit

Thunderbolt cables are certified by Intel, not USB-IF. Intel says certified Thunderbolt cables carry the Thunderbolt icon and a number, 3, 4 or 5, on the connector, and are tested for “bandwidth, signal integrity, and power delivery”. Its database is at thunderbolttechnology.net/products.

Thunderbolt 5 is built on USB4 Version 2.0 and gives 80Gbps of bi-directional bandwidth, or up to 120Gbps with Bandwidth Boost, according to Intel’s 2023 announcement, which also says it works over passive cables up to 1 metre. Intel argues the USB4 name alone guarantees less: in its 2026 certification post it says a product can carry a USB4 logo “with as little as 20 Gbps” of data bandwidth. For an external GPU, the laptop’s port sets the PCIe ceiling whatever the cable says, as our piece on what limits an eGPU sets out.

Questions people ask

What does USB 40Gbps 240W on a cable mean?

It is USB-IF’s certified cable logo. The cable passed compliance testing for data at 40Gbps and power up to 240W, the USB Power Delivery 3.1 maximum. Both numbers are part of one logo, printed or embossed on the plug.

Why does my 240W USB-C cable transfer files slowly?

A 240W logo with no Gbps figure marks a USB 2.0 Type-C cable. USB-IF says those carry data at up to 480Mbps and do not support USB 3.2, USB4 or Alt Mode. For fast data, the logo has to show 5, 20, 40 or 80Gbps.

Is a USB-C cable without a logo bad?

Not necessarily, but it is uncertified under current rules. USB-IF requires every USB-C to USB-C cable that passes compliance to carry a data-rate and power logo, so a new cable without one has not been through its programme. Anything the box claims rests on the maker alone.

Can I use a 40Gbps cable for USB 80Gbps?

USB-IF’s 2022 announcement says USB 80Gbps runs over existing 40Gbps passive USB-C cables, as well as newly defined 80Gbps active cables. Its current USB4 page describes 80Gbps operation “over 80 Gbps certified cables”. A cable certified at that speed carries the USB 80Gbps logo, at 60W or 240W.

Is a Thunderbolt cable the same as a USB4 cable?

Thunderbolt cables have their own certification, run by Intel, and carry the Thunderbolt icon with a 3, 4 or 5 on the connector. Thunderbolt 5 is built on USB4 Version 2.0, and Intel’s announcement quotes Microsoft calling it fully USB 80Gbps compliant.

How do I check if a USB-C cable is certified?

Look for the logo on the plug and the word CERTIFIED on the packaging logo, then search USB-IF’s certified product list at usb.org/products. It shows the last two years by default; widen the date filter for older cables.

Does USB-C mean USB4?

No. USB-IF says USB Type-C is a connector, and is not USB 3.2, USB4 or USB Power Delivery. A USB-C cable may support any of those, or only USB 2.0. The logo on the plug is what tells you which.