If you've ever stared at a drawer full of identical-looking USB-C cables, wondering which one supports fast charging or high-speed data transfer, you're not alone. USB-C cables vary wildly in capability—one might top out at 5W charging while another handles 100W and Thunderbolt 4—yet they all look the same. That's where WhatCable comes in. This tiny, free menu bar app for macOS reads the metadata your Mac already collects when you plug in a cable, then presents a plain‑English breakdown of what that cable can actually do. No more guesswork, no more wasted time swapping cables.

Why are USB-C cables so confusing?

USB-C is a universal connector standard, but the cables themselves are anything but uniform. A single USB-C cable can support anything from basic 5W charging to 100W power delivery, USB 2.0 to Thunderbolt 4 speeds, and optional features like video output or DisplayPort alt mode. Yet manufacturers rarely label cables clearly, and the connectors are all physically identical. This means you might plug a cable expecting 100W charging only to discover it chugs along at 5W. The confusion stems from the fact that a cable’s capabilities depend on its internal wiring and certification, not its exterior. Many people end up with drawers full of mismatched cables, relying on trial and error or expensive testers. That’s why a tool like WhatCable is so valuable—it eliminates the guesswork by revealing the hidden specification data your Mac already knows.

What is WhatCable and how does it simplify identifying cables?

WhatCable is a macOS menu bar application that automatically detects and displays the capabilities of any USB-C cable plugged into your Mac. Once installed, it sits discreetly in your menu bar. When you connect a cable—whether to a charger, peripheral, or display—WhatCable reads the cable data that macOS already collects from the cable’s internal chip. It then presents a clear summary in plain English, covering charging wattage, data speed, display support, and Thunderbolt compatibility. This means you no longer need a multimeter or special hardware to figure out if a cable supports 100W fast charging or USB 3.2 Gen 2. The app is built with Swift/SwiftUI and is fully open source, so you can inspect its code or contribute improvements. It’s available for free on GitHub with no tracking whatsoever.

How does WhatCable read cable information from a Mac?

Every USB-C cable contains a small chip called an E‑marker that stores metadata about the cable’s capabilities, such as maximum current, voltage, data speed, and alternate modes. When you plug a cable into your Mac, macOS queries this chip to negotiate power delivery and data transfer. WhatCable taps into that same system data—without any extra drivers or hardware—and parses the raw values into easy‑to‑understand labels. For example, what macOS reports as "2000 mA @ 20 V" becomes "40W charging" in WhatCable. The app runs entirely locally, so your cable data never leaves your machine. It’s built on low‑level APIs in Swift/SwiftUI that access the I/O Kit framework, making it lightweight and efficient. Plug in a cable, and the menu bar icon updates instantly with a summary; click it for more details.

What specific details can WhatCable reveal about a USB-C cable?

WhatCable gives you a complete breakdown of a cable’s capabilities, organized into clear categories:

• Charging wattage – Maximum power delivery supported (e.g., 5W, 60W, 100W).
• Data speed – USB version and transfer rate (e.g., USB 2.0 at 480 Mbps, USB 3.2 Gen 2 at 10 Gbps, Thunderbolt 3/4 at 40 Gbps).
• Display support – Whether the cable can carry video signals (e.g., DisplayPort alt mode, HDMI over USB-C).
• Thunderbolt – Explicit detection of Thunderbolt 3 or 4 capability, including daisy‑chaining support.
• Other features – Info on cable length, orientation (reversible), and any proprietary signals like Power Delivery 3.0.

All information is presented in plain English, so you don’t need to decode technical specs. This makes it easy to quickly identify which cable to use for fast charging a laptop versus syncing data to an external drive.

Is WhatCable safe to use? What about privacy and tracking?

WhatCable is designed with user privacy and security as top priorities. The app is open source under a permissive license, meaning anyone can review the code to verify there’s no hidden tracking, data collection, or telemetry. It operates completely offline—no internet connection is required, and it never sends any information to external servers. Because it only reads data from your Mac’s system APIs (which macOS already collects when a cable is plugged in), there’s no risk of transmitting sensitive information. The developer, Darryl Morley, has stated the app is free, contains no ads, and uses zero tracking. It runs in your menu bar and only processes cable events while the app is active. You can even inspect the entire source on GitHub and build it yourself if you prefer maximum control.

How can I get WhatCable and is it really free?

WhatCable is completely free of charge and open source. You can download it directly from the official GitHub repository: https://github.com/darrylmorley/whatcable. The page includes installation instructions, source code, and a releases section with pre‑built binaries for macOS. There is no premium tier, no in‑app purchases, and no subscription. Because the app is open source, you’re free to modify it to suit your needs or contribute bug fixes and features. It’s built in Swift/SwiftUI and requires macOS 11 or later. Simply download the latest release, drag it to your Applications folder, and launch it. The menu bar icon appears, and you’re ready to start identifying cables instantly. No registration, no email required—just download and use.