See how calm your heart is, beat by beat.

The time between heartbeats keeps changing. When you're relaxed it varies more; under stress it gets more regular. Heartstrip reads that variation (HRV) from a Bluetooth heart-rate sensor, removes sensor glitches, and estimates stress every five seconds with a model that runs in your browser.

Works with sensors that report beat-to-beat intervals: Elite CorSense, Polar H10 / H9 / Verity Sense, Garmin HRM-Pro, Wahoo TICKR and others. Needs Chrome or Edge on a laptop or Android; iPhone browsers don't support Web Bluetooth. On an iPhone, record in Elite HRV, export the reading's raw RR intervals, and open the file here.

Your recording is read in this browser only. Nothing is uploaded unless you use Newton, which sends the last 64 beats to Archetype AI.