This Free macOS App Will Tell You All About Your Nondescript USB-C Cable

A new Mac app can help you finally untangle the cable chaos happening in your desk drawer. It displays USB-C information on Apple silicon Macs in plain language, letting you know what each cable can actually do, including its data speed and power limits and whether it supports USB4 or Thunderbolt.

WhatCable looks at e‑marker chips inside each cable and displays its vendor ID, rated wattage, speed, and charging capabilities. It shows the charging power a Mac gets from a particular cable and highlights whether the port, charging brick, or device is limiting power transfer.

A tool like this one helps users understand issues like slow charging, unreliable external drives, or even monitors not reaching their full resolution and refresh rate. The one caveat is that a cable needs to be connected to some power source for WhatCable to work, but even your phone is sufficient.

The app is open source under the MIT license. There is a paid Pro version that provides more insight into the cables in use, including power negotiation timelines and more detailed health metrics for ports and devices. Power users and developers can also use a command‑line version to get JSON output for automation or testing.

While The Verge senior editor Sean Hollister found WhatCable to be mostly reliable and easy to use, some cables are designed to convey incorrect information about their capabilities. If you suspect that’s the case for one of your cables, you can check the app’s evolving cable database.