A free program for Android, by Tacx B.V..

Tacx is a tool for the performance analysis of bicycles and other sports equipment. It allows you to measure, calibrate, and visualise your bicycle or other sports equipment in order to optimise your performance. It is designed to be used by experienced cyclists, in order to measure and calibrate their equipment in the most accurate way.

Tacx allows you to measure the speed, the cadence, the distance, the elevation, the heart rate, and the power of your bicycle or other sports equipment. It is compatible with smart trainers and heart rate monitors, such as the Tacx Smart Trainer and the Garmin Live Sport.