Request a product

Apple Watch Series 6 vs Apple Watch Ultra 4

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

Better figure, where one is clearly better

AppleWatch Series 6AppleWatch Ultra 4
Overview
ReleasedSeptember 2020September 2026
Display
Case sizes40 mm or 44 mm49 mm
PanelLTPO OLEDLTPO OLED
Peak brightness1,000 nits3,000 nits
Always-on displayYesYes
Display detailAlways-On Retina LTPO OLED; 40mm 324 x 394 pixels and 759 sq mm; 44mm 368 x 448 pixels and 977 sq mm; wrist-down outdoor brightness up to 2.5 times Series 5Always-On Retina display with wide-angle OLEDs and LTPO3; 1Hz refresh; 422 x 514 pixels at 326 ppi; 1,245 sq mm display area; 1 nit minimum brightness; Night Mode for Ultra watch faces
Screen protection–Flat sapphire crystal front
Health and fitness
ECGYesYes
Blood oxygenYesYes
Skin temperatureNoYes
Sleep apnoea alertsNoYes
High blood pressure alertsNoYes
Body compositionNoNo
Fall detectionYesYes
Crash detectionNoYes
GPSSingle-bandDual-band (L1 and L5)
Water resistance50 m100 m
SensorsBlood oxygen sensor; electrical and third-generation optical heart sensors; 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; depth gauge to 40 m; water temperature sensor; compass; always-on altimeter (–500 m to 9,000 m); high-g accelerometer; high dynamic range gyroscope; ambient light sensor
Health featuresECG and Blood Oxygen apps, irregular-rhythm notifications; sleep tracking and automatic handwashing detection in watchOS 7; oxygen readings are for general wellness rather than medical useReadiness 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/GNSS and GymKit; always-on elevation tracking; dance, core training, functional strength training and cooldown workouts in watchOS 7Customisable Action button with Precision Start; custom workouts; Training Load and Workout Effort; customisable heart rate zones; VO2 max; Race Route; Pacer; cadence, stride length, ground contact time, vertical oscillation and running power; multisport workouts; offline maps with custom route creation; elevation alerts; Backtrack; swimming with water temperature; recreational diving to 40 m with Depth app and third-party dive computer apps; cycling with power meters; GymKit
Safety featuresFall detection and Emergency SOS; international emergency calling on cellular versions in supported regionsEmergency SOS and Find My via satellite; Emergency SOS; international emergency calling; Siren; 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 50 hours
In low-power mode–Up to 84 hours
Mobile data optionYesYes
Works withiPhoneiPhone
ChipS6S11
Storage32 GB64 GB
Battery life detailBuilt-in rechargeable lithium-ion batteryUp to 50 hours of normal use; up to 84 hours in Low Power Mode; up to 18 hours of outdoor workout, 25 hours in Extended Workout and 45 hours in Max Extended Workout
Charging1 m magnetic charging cable; full charge in under 1.5 hours, according to Apple's launch announcementFast charging to 80% in about 45 minutes; 15 minutes for up to 18 hours of normal use; 5 minutes for up to 10 hours of sleep tracking
ConnectivityW3 wireless chip and U1 Ultra Wideband chip; Wi-Fi 802.11b/g/n at 2.4GHz and 5GHz; Bluetooth 5.0; cellular versions add LTE and UMTS; requires iPhone 6s or later with iOS 14 at launchGPS + Cellular only (model A3579) with 5G RedCap and LTE; satellite communications; Wi-Fi 4 (802.11n) at 2.4GHz and 5GHz; Bluetooth 5.3; second-generation Ultra Wideband chip; NFC for Apple Pay; precision dual-frequency GPS (GPS, Galileo, QZSS and BeiDou)
Design
Weight (lightest version)30.5 g63 g
SoftwarewatchOSwatchOS
Case materialsAluminium, stainless steel or titanium; ceramic and sapphire crystal back; 50 m rating under ISO 22810:2010 for shallow-water swimmingGrade 5 titanium case (100% recycled titanium) with ceramic and zirconia back; water resistant to 100 m (ISO 22810:2010); EN13319 recreational diving to 40 m; IP6X dust resistant; tested to MIL-STD 810H
Size40mm 40 x 34 x 10.7 mm, aluminium 30.5 g, steel 39.7 g or titanium 34.6 g; 44mm 44 x 38 x 10.7 mm, aluminium 36.5 g, steel 47.1 g or titanium 41.3 g; case weights exclude bands49 x 44 x 12 mm; 63.0 g (natural) or 63.1 g (black)
BandsApple Watch Studio offers case and band choices; Solo Loop and Braided Solo Loop introduced with Series 6; Nike and Hermès bands and faces also offeredFits 130–210 mm wrists
ColoursSilver, Space Grey, Gold, Blue or (PRODUCT)RED aluminium; Silver, Graphite or Gold stainless steel; natural or Space Black (DLC) titanium; Nike Silver or Space Grey; Hermès steel or Space Black steelNatural or Black titanium
In the boxWatch, band or loop and 1 m magnetic charging cable; no USB power adapterApple Watch Ultra 4, strap, Apple Watch Magnetic Fast Charger to USB-C Cable (1 m)

More comparisons