The Apple Watch Series 12 and Apple Watch Ultra 4 bring new health sensors, a new chip, and more detailed recovery insights to Apple's smartwatch lineup, so how do they compare?Both models feature the S11 chip, 4GB of RAM, 64GB of storage, and the new Health Sensing System, which measures heart rate every five seconds throughout the day. They also share Readiness, Recovery HRV, daytime vitals, improved step tracking, hypertension notifications, sleep apnea notifications, Sleep Score, and more. This means that the Ultra 4's higher price does not buy you more advanced everyday health tracking.The Apple Watch Series 12 starts at $399, while the Apple Watch Ultra 4 starts at $799. The gap narrows if you want a premium case material, with the titanium Series 12 starting at $699. This year, the Series 12 also gains a ceramic option starting at $899, making it more expensive than the Ultra despite its smaller size and shorter battery life.The Apple Watch Ultra continues to focus on durability, extended battery life, and additional capabilities for activities like diving and exploration. Our guide helps to answer the question of how to decide which of these two Apple Watches is best for you. The differences between the Apple Watch Series 12 and ‌Apple Watch Ultra 4‌ are as follows:Apple Watch Series 12‌Apple Watch Ultra 4‌Rounded design with a thinner case and front glass that curves at the edgesRugged design with a thicker case and slightly raised edges to protect the flat front crystalAluminum, polished titanium, or polished ceramic caseBlasted titanium caseAluminum and titanium: 42mm and 46mm case sizesCeramic: Marketed as 42mm and 46mm, with actual heights of 43mm and 47mm49mm case size42mm aluminum and titanium: 37mm case width43mm ceramic: 37mm case width46mm aluminum and titanium: 40mm case width47mm ceramic: 41mm case width49mm titanium: 44mm case widthAluminum and titanium: 9.7mm case depthCeramic: 9.85mm case depth12mm case depthWeighs 31.5 to 52.9 grams depending on case size, material, finish, and connectivityNatural titanium: 63.0 gramsBlack titanium: 63.1 gramsAluminum: Ceramic Shield 2 front glassTitanium and ceramic: Sapphire front crystalSapphire front crystal42mm: 374 by 446 pixels46mm: 416 by 496 pixels422 by 514 pixels42mm: 970 sq mm display area46mm: 1,196 sq mm display area1,245 sq mm display areaUp to 2,000 nits peak brightnessUp to 3,000 nits peak brightnessExclusive Wayfinder, Modular Ultra, and Orienteering facesNight Mode on Apple Watch Ultra facesCustomizable Action button, including Precision Start for workouts86-decibel Siren to attract attentionSingle speakerDual speakersSingle microphone with Voice IsolationThree-microphone array with beamforming and wind noise mitigationAluminum: GPS or GPS + Cellular optionsTitanium and ceramic: GPS + CellularGPS + Cellular on all modelsU.S. TDD cellular bands: 5G n38, n40, and n41; LTE 38, 39, 40, and 41U.S. TDD cellular bands: 5G n38, n40, n41, and n53; LTE 38, 39, 40, 41, and 53Satellite communications for Emergency SOS, Messages, and Find MyPrecision L1 GPSPrecision dual-frequency GPS (L1 and L5)GPS, GLONASS, Galileo, QZSS, and BeiDou supportGPS, Galileo, QZSS, and BeiDou supportWater resistant to 50mWater resistant to 100mSuitable for swimming and snorkelingSuitable for swimming, snorkeling, high-speed water sports, and recreational scuba diving to 40mDepth gauge and Depth app to 6mDepth gauge and Depth app to 40mTested to MIL-STD 810HEN13319 certification for recreational scuba divingRecommended ambient operating temperature of 0°C to 35°COn-wrist operating temperature of -20°C to 55°CAlways-on altimeterAlways-on altimeter with expanded operating range from -500m to 9,000mOperating altitude from 0m to 3,000mOperating altitude from -500m to 9,000mUp to 24 hours of normal useUp to 50 hours of normal useUp to 38 hours in Low Power ModeUp to 84 hours in Low Power ModeUp to 10 hours of standard outdoor workout trackingUp to 18 hours of standard outdoor workout trackingUp to 25 hours in Extended Workout mode with full GPS and heart rate readingsUp to 45 hours in Max Extended Workout mode, retaining GPS readings every secondCharge from 0 to 80% in about 30 minutesCharge from 0 to 80% in about 45 minutes15 minutes of charging for up to 12 hours of normal use15 minutes of charging for up to 18 hours of normal useAluminum: Dark Bronze, Light Gold, Black, and Space GrayTitanium: Radiant Gold and NaturalCeramic: Pearl White and Night BlueNatural Titanium or Black TitaniumHermès: Silver or Radiant Gold titaniumHermès: Natural titanium40% recycled content in aluminum and titanium models45% recycled contentAluminum: Starts at $399Titanium: Starts at $699Ceramic: Starts at $899Hermès: Starts at $1,399Standard: Starts at $799Hermès: Starts at $1,499For most users, the Apple Watch Series 12 is the better choice. It offers the same performance, health sensors, Readiness insights, and Audio Intelligence features as the Ultra 4 in a thinner, lighter device. The aluminum model delivers these benefits for $400 less, making it the stronger option for everyday use and regular workouts.The Ultra 4's most broadly useful advantage is battery life. Its longer endurance makes overnight wear and extended workouts easier to fit around charging. You do not need to be an endurance athlete to appreciate less frequent charging, but the premium is easier to justify if the Series 12 cannot comfortably cover your usual activities and charging habits.For hiking away from cellular coverage, recreational scuba diving, or very long events, the Ultra has a clearer purpose. Satellite communications, dual-frequency GPS, greater water resistance, and extended workout modes address needs that the Series 12 cannot fully meet. The Action button and brighter display may also appeal to enthusiasts who simply want more capable hardware.Size and appearance remain substantial trade-offs. The Ultra is considerably bulkier and heavier despite offering a display only slightly larger than the 46mm Series 12's. The Series 12 is more discreet and offers polished titanium and ceramic finishes, making it better suited to buyers who prioritize comfort or appearance. Try on the Ultra before buying if you are unsure about its size.The decision becomes closer if you already want the titanium Series 12, since its starting price is just $100 below the Ultra's. At that point, paying more for longer battery life and additional hardware is reasonable if you are comfortable with the larger case. The $899 ceramic Series 12 is primarily a choice of material and finish; choose it because you prefer its appearance, rather than expecting more capabilities than the $799 Ultra.Related Roundups: Apple Watch 12, Apple Watch Ultra 4Buyer's Guide: Apple Watch (Buy Now), Apple Watch Ultra (Buy Now)Related Forum: Apple WatchThis article, "Apple Watch Series 12 vs. Ultra 4 Buyer's Guide" first appeared on MacRumors.comDiscuss this article in our forums