Parallax: Device Accuracy

Parallax analyzes the accuracy of your sports devices. Record a session with two or more devices (watches, bike computers, chest straps, power meters) and compare their files second by second. What you can do - Compare FIT, GPX, TCX and KML files (also inside a ZIP) from several devices in the same session: GPS track on the map and overlaid charts of heart rate, pace, speed, elevation, cadence and power. - See the accuracy of each device against the reference you choose: time within tolerance, mean error and bias, with a grade per metric from A+ to F. - Audit a file: Parallax checks a single file for GPS jumps, doubtful heart rate values and calculated data. Without an account, the analysis runs on your iPhone and the file never leaves it. - Import workouts from Apple Health with their route and heart rate, converted to FIT without filling anything in. Choose them one by one or turn on automatic sync for the sources you want (Apple Watch and other apps that save workouts to Health). - Connect your Garmin and Polar accounts to import activities automatically and create the comparison when two devices match. - Open or share files with Parallax from other apps, such as Files, Mail or your device's app. - Upload files in the background, with retries if the connection drops. - Get a notification when a comparison is created. - Share a comparison with a public link, with a privacy zone and a verifiable seal that lets anyone check the files are the originals. What each device records Parallax shows the data as the device stores it. If a value is calculated or processed by another app, it says so. The accuracy grade is our own assessment with a documented method, not a manufacturer certification. Parallax does not provide medical advice. Privacy From Apple Health, Parallax only reads workouts, their routes and heart rate, and it writes nothing to Health. Your data is not sold or used for advertising. The app contains no ads. Account You need a Parallax account (email, Apple or Google) to save comparisons. File audits work without an account. Some features require an account with a subscription.