Apple Watch SE (1st generation) vs Apple Watch Series 12

Every spec side by side, from each maker's published figures.

Better figure, where one is clearly better

Watch SE (1st generation) compared with Watch Series 12
AppleWatch SE (1st generation)AppleWatch Series 12
Overview
ReleasedSeptember 2020September 2026
Display
Case sizes40 mm or 44 mm42 mm or 46 mm
PanelLTPO OLEDLTPO OLED
Peak brightness1,000 nits2,000 nits (better)
Always-on displayNoYes
Display detailRetina LTPO OLED; 40mm 324 x 394 pixels and 759 sq mm; 44mm 368 x 448 pixels and 977 sq mmAlways-On Retina display with wide-angle OLEDs and LTPO3; 1Hz refresh; 374 x 446 pixels (42mm) or 416 x 496 pixels (46mm) at 326 ppi; 970 or 1,196 sq mm display area; 1 nit minimum brightness
Screen protectionIon-X glassCeramic Shield 2 (aluminium cases); sapphire front crystal (titanium and ceramic cases)
Health and fitness
ECGNoYes
Blood oxygenNoYes
Skin temperatureNoYes
Sleep apnoea alertsNoYes
High blood pressure alertsNoYes
Body compositionNoNo
Fall detectionYesYes
Crash detectionNoYes
GPSSingle-bandSingle-band
Water resistance50 m50 m
SensorsSecond-generation optical heart sensor; compass, always-on altimeter, accelerometer up to 32 g-forces, gyroscope and ambient light sensorHealth Sensing System with third-generation electrical heart sensor, always-on optical heart sensor, blood oxygen sensor and temperature sensor; compass; always-on altimeter; high-g accelerometer; high dynamic range gyroscope; ambient light sensor; depth gauge to 6 m; water temperature sensor
Health featuresHigh and low heart rate notifications; Noise app; sleep tracking and automatic handwashing detection in watchOS 7Readiness app; Vitals app (heart rate, respiratory rate, wrist temperature, blood oxygen, sleep duration and HRV); Recovery HRV; high-frequency background heart rate tracking; ECG app; Blood Oxygen app; irregular rhythm notifications; high and low heart rate notifications; hypertension notifications; sleep apnoea notifications; sleep stages and sleep score; Cycle Tracking with fertile window and retrospective ovulation estimates, perimenopause and menopause support; Medications; Mindfulness; Noise
Fitness featuresGPS, GLONASS, Galileo and QZSS; GymKit; Activity rings; elevation and compass information; dance, functional strength and core workouts in watchOS 7Custom workouts; Training Load; customisable heart rate zones; VO2 max; Race Route; Pacer; cadence, stride length, ground contact time, vertical oscillation and running power; automatic track detection; multisport workouts; offline maps with custom route creation; Backtrack; pool and open-water swimming with SWOLF; cycling power zones with Bluetooth accessories; GymKit
Safety featuresFall Detection and Emergency SOS; international emergency calling on cellular versions in supported regionsEmergency SOS; international emergency calling; Fall Detection; Crash Detection; Check In; Backtrack; Last Emergency Call Availability Waypoint; torch; noise monitoring
Battery and connections
Battery life (maker's claim)Up to 18 hoursUp to 24 hours
In low-power mode–Up to 38 hours
Mobile data optionYesYes
Works withiPhoneiPhone
ChipS5S11
Storage32 GB64 GB (better)
Battery life detailBuilt-in rechargeable lithium-ion batteryUp to 24 hours of normal use; up to 38 hours in Low Power Mode; up to 10 hours of outdoor workout
ChargingMagnetic charging cable; retail packaging updated to USB-C in September 2021; USB power adapter sold separatelyFast charging to 80% in about 30 minutes; 15 minutes for up to 12 hours of normal use; 5 minutes for up to 10 hours of sleep tracking
ConnectivityW3 wireless chip; Wi-Fi 802.11b/g/n at 2.4GHz; Bluetooth 5.0; cellular versions add LTE and UMTS; requires iPhone 6s or later with iOS 14 at launch; Family Setup allows a family member without an iPhone to use a cellular watch managed from an organiser's iPhoneWi-Fi 4 (802.11n) at 2.4GHz and 5GHz; Bluetooth 5.3; second-generation Ultra Wideband chip; NFC for Apple Pay; Precision L1 GPS (GPS, GLONASS, Galileo, QZSS and BeiDou); GPS + Cellular models (A3582, A3587) with 5G RedCap and LTE
Design
Weight (lightest version)30.49 g (better)31.5 g
SoftwarewatchOSwatchOS
Case materialsRecycled aluminium case; ceramic and sapphire crystal back; 50 m water resistance under ISO 22810:2010 for shallow-water swimming100% recycled aluminium or 3D-printed 100% recycled titanium case with zirconia back, or ceramic case; water resistant to 50 m (ISO 22810:2010); IP6X dust resistant
Size40mm 40 x 34 x 10.7 mm, GPS 30.49 g or cellular 30.68 g; 44mm 44 x 38 x 10.7 mm, GPS 36.20 g or cellular 36.36 g; case weights exclude bands42mm is 42 x 37 x 9.7 mm (ceramic 43 x 37 x 9.85 mm); 46mm is 46 x 40 x 9.7 mm (ceramic 47 x 41 x 9.85 mm); lightest is the 42mm aluminium GPS + Cellular at 31.5 g, heaviest the 46mm Night Blue ceramic at 52.9 g
BandsCompatible with Apple Watch bands including Solo Loop and Braided Solo Loop; Nike editions have exclusive bands and facesFits 130–200 mm wrists (42mm) or 140–245 mm wrists (46mm)
ColoursSilver, Space Grey or Gold aluminium; Nike Silver or Space GreyAluminium in Dark Bronze, Light Gold, Black and Space Grey; titanium in Radiant Gold and Natural; ceramic in Pearl White and Night Blue
In the boxWatch, band or loop and 1 m magnetic charging cable; no USB power adapter; later packaging supplies a USB-C cableApple Watch Series 12, strap, Apple Watch Magnetic Fast Charger to USB-C Cable (1 m)

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