Apple Watch Series 12 vs Series 10: New Health Sensors and 24-Hour Battery

Apple Watch Series 12 keeps the Series 10 design but adds the Health Sensing System with an always-on optical heart sensor measuring heart rate every five seconds, plus a 0–10 Readiness score. Battery life rises from 18 to 24 hours, and a 15-minute charge delivers up to 12 hours of use. Pricing starts at $399.

• Health Sensing System measures heart rate every 5 seconds and HRV up to 24x more often
• Battery life rises from 18 to 24 hours; 15-minute charge gives 12 hours
• Readiness score of 0–10 combines activity, sleep and training load
• Aluminum models get Ceramic Shield 2 glass; pricing starts at $399