TL;DR: USB-C is just the connector shape; the cable inside can be very different. Certified USB-C cables are labeled with two numbers: power (60W or 240W) and data speed (USB 2.0 480Mbps, 5Gbps, 20Gbps, 40Gbps or 80Gbps). A 60W cable is fine for phones and small laptops; 240W is for powerful laptops. For fast external drives or monitors, you need a 20Gbps-plus data cable; for docks and Thunderbolt gear, a 40Gbps or 80Gbps (USB4/Thunderbolt) cable. Look for the USB-IF certified logo on the cable or box.
Last updated: October 23, 2026. Based on USB-IF specifications and logo guidelines.
Two USB-C cables can look identical yet charge at different speeds or move data 160 times faster than each other. This guide explains the labels using the USB Implementers Forum’s (USB-IF) own documents, so you can buy the right cable once.
Why are USB-C cables different?
Because USB-C describes the plug, not what the cable can do. Inside, cables differ in how much current they carry and how many high-speed data wires they have. The USB-IF, which runs the USB standards, introduced cable logos in 2021 so buyers can tell them apart. Its announcement says certified cables “feature logos highlighting support for 60W or 240W of power as defined by the… USB Power Delivery (USB PD) 3.1 Specification.”
What do the 60W and 240W ratings mean?
They’re the maximum charging power the cable is certified to carry. USB-IF’s logo guidelines give the example of a cable “that supports 20V at 3A,” which is labeled 60W. USB PD 3.1 “unlocks up to 240W over a USB Type-C cable and connector,” per USB-IF.
| Cable rating | Max power | Good for |
|---|---|---|
| 60W | 20V × 3A | Phones, tablets, earbuds, most thin laptops |
| 240W | 48V × 5A (USB PD 3.1 Extended Power Range) | Gaming and workstation laptops, high-power chargers |
Cables rated above 60W contain an e-marker chip that tells the charger what the cable can handle. If you use a 60W cable with a 100W charger, the charger simply limits power to 60W; it won’t damage anything.
Your charger and device matter too. A 240W cable won’t make a 20W phone charger faster. For wireless charging, see our Qi2 vs MagSafe guide.
What do the data speeds mean?
They’re the maximum transfer rate between devices. USB-IF requires every certified USB-C to USB-C cable, except basic USB 2.0 ones, to be “marked with the appropriate data rate they can support,” per its cables page.
| Label | Speed | Older name | Good for |
|---|---|---|---|
| (power logo only) | 480Mbps | USB 2.0 | Charging, keyboards, mice |
| USB 5Gbps | 5Gbps | USB 3.2 Gen 1 | Flash drives, basic hard drives |
| USB 20Gbps | 20Gbps | USB 3.2 Gen 2×2 / USB4 20Gbps | Fast SSDs |
| USB 40Gbps | 40Gbps | USB4 / Thunderbolt 3–4 class | Docks, external SSDs, monitors |
| USB 80Gbps | 80Gbps | USB4 Version 2.0 / Thunderbolt 5 class | High-end docks, multiple displays |
The certified logos combine both numbers, for example “40Gbps/240W” or “20Gbps/60W.” USB-IF’s guideline lists combined logos for 5, 20, 40 and 80Gbps, each at 60W or 240W.
Why does my USB-C cable charge slowly?
Usually because the cable, charger or device is the bottleneck. Common causes:
- A 60W cable on a laptop that can take more, such as a 100W or 140W model.
- A low-power charger. Check the watts printed on the charger.
- The device’s own limit. Many phones charge at far below 60W regardless of cable.
- A damaged or uncertified cable. Replace frayed or loose cables.
What’s the difference between USB4 and Thunderbolt cables?
They overlap: Thunderbolt 4 and 5 are built on USB4, and good USB4 cables work with Thunderbolt devices. Intel certifies Thunderbolt cables, which are marked with a lightning-bolt icon. A 40Gbps or 80Gbps USB4 cable is generally the right match for Thunderbolt docks; check your dock’s manual if it requires a specific Thunderbolt-certified cable. Passive high-speed cables are often short, so longer runs may need active cables.
Which USB-C cable should you buy?
Match the cable to the job; you don’t need the most expensive one everywhere.
| If you want to… | Buy |
|---|---|
| Charge a phone or tablet | 60W USB-C cable (USB 2.0 is fine) |
| Charge a powerful laptop | 240W cable |
| Use a fast external SSD | 20Gbps or faster |
| Connect a monitor or dock | 40Gbps or 80Gbps (USB4/Thunderbolt) |
| Have one cable for everything | 40Gbps/240W or 80Gbps/240W, short length |
Tips:
- Look for the USB-IF certified logo on the cable or packaging. USB-IF says the logo “is required to be on the cable” and is verified during testing.
- Buy from trusted sellers. Counterfeit cables may carry fake markings.
- Label your cables with tape or colored ties so you know which is fast.
In the EU, a common-charger law has made USB-C the standard port for new phones, tablets and many other devices, and it applies to laptops from April 28, 2026, so one good cable set covers more of your gear each year. For laptop buying advice, see our best time to buy a laptop guide.
FAQ
Are all USB-C cables the same?
No. USB-C is only the connector shape. Cables differ in charging power (60W or 240W) and data speed (480Mbps up to 80Gbps). Certified cables show both on a USB-IF logo.
What does 240W on a USB-C cable mean?
It means the cable is certified to carry up to 240 watts, the maximum under USB Power Delivery 3.1. It’s needed only for high-power laptops and chargers; it works fine with lower-power devices too.
Can I use a 240W cable to charge my phone?
Yes. The phone and charger negotiate a safe power level, so a 240W cable is safe for any USB-C device. It just won’t charge faster than the phone and charger allow.
How can I tell how fast my USB-C cable is?
Check for a USB-IF logo on the connector or packaging, such as “40Gbps/240W.” A cable with only a 60W or 240W power logo is a USB 2.0 data cable (480Mbps).
Is Thunderbolt the same as USB-C?
No. Thunderbolt is a high-speed standard that uses the USB-C connector. Thunderbolt 4 and 5 are based on USB4, so 40Gbps and 80Gbps USB4 cables generally work with Thunderbolt devices.
Why won’t my USB-C cable work with my monitor?
It’s probably a USB 2.0 charging cable, which can’t carry video. Use a 40Gbps or 80Gbps USB4/Thunderbolt cable, or one specifically rated for video (DisplayPort Alt Mode).
Sources checked October 23, 2026: USB-IF USB Type-C Cable Logo Usage Guidelines (January 2026), USB-IF Cables and Connectors page, USB-IF September 2021 logo announcement.
