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Will It Work? · Guide

USB-C cable ratings: 60 W, 240 W and the e-marker chip

By Bulan Sarkar, founder of ElectronicsInfoline (since 2000)

Two USB-C cables can look identical and still charge a laptop at different speeds, because the limit is printed on the cable, not shaped into the plug. This guide reads the ratings straight from the USB-IF documents: what 60 W and 240 W mean, what the e-marker chip does, and how the data speed fits in.

A 60 W USB-C cable is rated 20 V at 3 A; a 240 W cable is rated 48 V at 5 A. Standard cables carry 3 A, and any cable rated above 3 A must have an e-marker chip in the plug that tells the charger so. Data speed (USB 5Gbps to 80Gbps) is a separate rating.

The two power ratings

The USB Type-C specification rates standard cables for 3 A and lets electronically marked cables carry up to 5 A (USB-IF). The USB-IF tests cables at 60W (20 V, 3 A) for the standard power range and 240W (48 V, 5 A) for the extended range (USB-IF).

USB-C cable ratings: 60 W and 240 WA 60 W cable carries 20 V at 3 A. A 240 W cable carries 48 V at 5 A and has an e-marker chip in the plug, which every cable rated above 3 A must have.60 W cable20 V × 3 Ae-marker chip240 W cable48 V × 5 A, chip in the plugA 3 A cable may also have a chip; above 3 A it must.
Figure 1. USB-IF figures: a 60 W cable is tested at 20 V, 3 A; a 240 W cable at 48 V, 5 A. Any cable rated above 3 A carries an e-marker chip that tells the charger what it can take.

Before PD 3.1, USB Power Delivery stopped at 100 W: 20 V on a cable rated 5 A (USB-IF). PD 3.1 added 28, 36, 48 V for up to 240 W, and the Type-C specification Release 2.1 added the 240 W cable to carry it (USB-IF).

Charging power is the lowest of three limitsCharger 100 W, cable 60 W, device 100 W. The result is 60 W.Charger offers100 WCable carries60 WDevice accepts100 WYou get60 W
Figure 2. A 100 W charger and a 100 W laptop on a 60 W cable: the cable is the lowest limit, so the laptop gets 60 W.

What the e-marker chip does

All cables that are full-featured or rated above 3 A are electronically marked (USB-IF). The chip tells the charger what the cable can take. A cable without one counts as a standard 3 A cable, so a 5 A charger on it stays at 3 A.

The names on the box

Certified USB-C to USB-C cables carry a mark with both the data rate and the power, for example 20Gbps/60W (USB-IF). The data rates are named by speed: USB 80Gbps, 40Gbps, 20Gbps, 10Gbps and 5Gbps (USB-IF). Spec terms like SuperSpeed Plus are not meant for packaging (USB-IF), so a box that leads with them is not following the USB-IF naming.

How a certified USB-C cable is named: data speed plus powerData speed names USB 80Gbps, 40Gbps, 20Gbps, 10Gbps and 5Gbps, each paired with a 60W or 240W power rating, for example 20Gbps with 60W.Data rate80Gbps40Gbps20Gbps10Gbps5GbpsPower60W240WExample mark20Gbps60W
Figure 3. The USB-IF names a cable by its data rate (USB 5Gbps up to USB 80Gbps) and its power (60W or 240W). Its own example: a 20Gbps cable that carries 20 V at 3 A takes the 20Gbps/60W mark.

Tips and tricks

  • Look for the watt figure on the cable or its packaging. No figure printed? Treat it as 60 W (3 A), the standard rating.
  • Buy 240 W only if a charger or laptop needs more than 100 W. A 100 W (5 A) cable covers everything up to 20 V at 5 A.
  • Charging fine but external drives slow? The cable may be a USB 2.0 cable rated for full power. The data rate is a separate number.

What we would do

For phones and small laptops, a 60 W cable is enough. For a laptop that charges at 65 W to 100 W, use a 5 A (100 W) or 240 W cable. For a 140 W or bigger laptop charger, only a 240 W cable will do. If you also move files, buy one rated for the data speed you need, since that is the one figure the power rating tells you nothing about.

To check a whole setup (charger label, cable, device), use the charger and cable checker.

Questions people ask

What does 240W on a USB-C cable mean? It is tested for 48 V at 5 A, the top of USB Power Delivery since PD 3.1. It has an e-marker chip, and it works on lower-power chargers too.

Is a 60 W USB-C cable enough for my laptop? Up to 60 W, yes: it carries 20 V at 3 A. A laptop that charges at 65 W or more will charge more slowly on it, because the cable stops the charger at 3 A.

What is an e-marker chip? A small chip in the plug that tells the charger and the device what the cable can carry. The USB Type-C specification requires it in every cable rated above 3 A, and in full-featured data cables.

Does a faster data cable charge faster? No. Data speed and power are separate ratings. A USB 40Gbps cable can be rated 60W, and a USB 2.0 cable can be rated 240W. Read both halves of the name.

Sources

Each figure on this page is quoted from the source below or worked out from them. Sources checked , each quote read again against the source in a second pass.

  1. USB-IF, USB Type-C Cable and Connector Specification, Release 2.0 (August 2019): The USB Type-C receptacle is specified for current capability of 5 A whereas standard USB Type-C cable assemblies are rated for 3 A. [...] Also, USB Type-C cable assemblies designed for USB PD and appropriately identified via electronic marking are allowed to support up to 5 A. usb.org/sites/default/files/USB%20Type-C%20Spec%20R2.0%20-%2…
  2. USB-IF, USB Type-C Cable and Connector Specification, Release 2.0 (August 2019): All cables that are either full-featured and/or are rated at more than 3 A current are Electronically Marked Cables. usb.org/sites/default/files/USB%20Type-C%20Spec%20R2.0%20-%2…
  3. USB-IF, USB Active Cable Thermal Compliance Test Specification, Revision 0.92 (draft): Power delivery is set to maximum specification: 60W (20V, 3A) for SPR cable, or 240W (48V, 5A) for EPR cable. usb.org/sites/default/files/USB%20Active%20Cable%20Thermal%2…
  4. USB-IF, USB Type-C® Cable Logo Usage Guidelines (Jan 2026): In order to pass through the USB-IF Compliance Program, all USB-C® to USB-C cables must be labeled using the appropriate data rate and power wattage cable logo. For example, a USB 20Gbps cable that supports 20V at 3A must be marked with the Combined Performance and Power 20Gbps/60W logo. usb.org/sites/default/files/usb_type-c_cable_logo_usage_guid…
  5. USB-IF, USB-IF Licensed Mark(s) Requirements (last updated January 2026): USB-IF Test Procedure for USB Power Delivery 3.2 Standard Power Range and Hi-Speed USB Type-C® cables (for the 60w designation) or for USB Power Delivery 3.2 Extended Power Range and Hi-Speed USB Type-C® cables (for the 240w designation). usb.org/sites/default/files/trademark_license_agreement_lice…
  6. USB-IF, USB Data Performance Language Usage Guidelines from USB-IF (Jan 2024): The USB4® and USB 3.2 specifications together identify five transfer rates – 80Gbps, 40Gbps, 20Gbps, 10Gbps, and 5Gbps. usb.org/sites/default/files/usb_data_performance_language_us…
  7. USB-IF, USB Data Performance Language Usage Guidelines from USB-IF (Jan 2024): NOTE: USB4® Version 2.0, USB4® Version 1.0, USB 3.2, SuperSpeed Plus, Enhanced SuperSpeed and SuperSpeed+ are defined in the USB specifications however these terms are not intended to be used in product names, messaging, packaging or any other consumer-facing content. usb.org/sites/default/files/usb_data_performance_language_us…
  8. USB-IF, USB Charger (USB Power Delivery) | USB-IF: Announced in 2021, the USB PD Revision 3.1 specification is a major update to enable delivering up to 240W of power over full featured USB Type-C® cable and connector. Prior to this update, USB PD was limited to 100W using a solution based on 20V using USB Type-C cables rated at 5A. usb.org/usb-charger-pd
  9. USB-IF, USB Promoter Group Announces USB Power Delivery Specification Revision 3.1 (Developer Update, May 26, 2021): The USB Type-C specification has also been updated with Release 2.1 to define 240W cable requirements, and with the updated USB PD protocol and power supply definition, this extends the applicability of USB PD to a large number of applications where 100W wasn't adequate. usb.org/sites/default/files/2021-05/USB%20PG%20USB%20PD%203.…

Author: Bulan Sarkar · Report an error

Numbers here are quoted from standards bodies and makers, or worked out from them. Nothing on this page was measured or tested by us.