A new macOS app called TrackWeight lets you use your MacBook’s Force Touch trackpad as a precise digital weighing scale. Built by Canadian developer Krish Shah, the application taps into Apple’s pressure-sensitive sensors to measure weight with surprising accuracy, all without any additional hardware.
To use it, you place your finger on the trackpad and gently rest an object on it. The app reads the pressure data and converts it into grams. Your finger must stay in contact for the reading to work, since the sensor requires capacitance to register force. The app runs locally on your MacBook, provided it’s a Force Touch model released in 2015 or later.
The Tech Behind the Trick
At the core of TrackWeight is Open Multi-Touch Support, a macOS library by Takuto Nakamura. It gives developers access to low-level touch data, including pressure, angle, and position, that is normally hidden behind Apple’s private APIs. Shah’s app uses this stream of sensor data to translate pressure into weight, using the Force Touch hardware built into newer MacBooks.
The calibration process is simple. Shah placed his MacBook on a conventional digital scale, added objects while touching the trackpad, and compared the readings. According to him, the pressure data from the system came labeled in grams, which made conversion unnecessary. He claims the app can handle objects weighing up to 3.5 kilograms with reasonable accuracy.
In a series of posts on X, Shah shared footage of his tests, comparing video frames of the MacBook on a digital scale with TrackWeight’s readings. “It’s pretty accurate,” he wrote. He explained that the Force Touch sensor is essentially a pressure pad that mimics clicks using haptic feedback.
Experimental, Not Commercial
There are limitations. You cannot weigh objects without your finger staying on the trackpad. Metal items might trigger false readings unless you place a piece of paper or cloth in between. The physical size of the trackpad also limits what you can weigh. And if you try to put something too heavy on it, you risk damaging your laptop.
TrackWeight is open source, licensed under MIT, and available now on GitHub. You will need macOS 13 or later, a Force Touch MacBook, and Xcode to build and run the app. App Sandbox must be disabled because the app relies on low-level hardware access.
This isn’t meant to replace a digital scale. It’s an experiment that works well for small objects, demonstrations, or curiosity. As Shah makes clear on the GitHub repository, this is not intended for critical or commercial use.
