Testing conducted by Apple in March 2015 using preproduction Apple Watch and software paired with an iPhone using preproduction software. All-day battery life is based on 18 hours with the following use: 90 time checks, 90 notifications, 45 minutes of app use, and a 30-minute workout with music playback from Apple Watch via Bluetooth, over the course of 18 hours. Battery life varies by use, configuration, and many other factors; actual results will vary.
Watch Test Up to 48 hours
Testing conducted by Apple in March 2015 using preproduction Apple Watch and software paired with an iPhone using preproduction software with 5 time checks (4 seconds each) per hour. Battery life varies by use, configuration, and many other factors; actual results will vary.
Power Reserve Up to 72 hours
If your battery gets too low, Apple Watch automatically switches into Power Reserve mode so you can continue to see the time for up to 72 hours. Testing conducted by Apple in March 2015 using preproduction Apple Watch and software with 4 time checks (4 seconds each) per hour. Battery life varies by use, configuration, and many other factors; actual results will vary.