The evolution of the Apple Watch is characterized by relatively small, incremental updates each generation. Year after year, these small changes inevitably invite the question… “So what’s actually new this year?”. To answer this question, new hardware features between each generation of the Apple Watch are enumerated below.

Jump to Series X

Series 0

Released April 24, 2015 - The original Apple Watch had a large variety of sensors though ultimately suffered from poor performance.

  • AMOLED Retina display (450 nits brightness, Force Touch, sizes 38mm and 42 mm)
  • Apple S1 SiP
  • 8 GB onboard storage
  • 512MB RAM
  • NFC
  • WiFi 802.11b/g/n
  • Bluetooth 4.0 LE
  • Accelerometer
  • Gyroscope
  • Heart rate sensor
  • Ambient light sensor
  • Microphone
  • Speaker
  • Linear actuator Taptic Engine
  • IPX7 (splash) water resistance (1 meter)
  • Edition: 18 karat gold

Series 1

Released September 16, 2016 - The ‘Series 1’ was Apple’s attempt to correct the CPU issues that plagued the original Apple Watch (a.k.a. ‘Series 0’). [Performance Release]

  • Apple S1P dual-core processor
  • OLED Retina display (1st Generation)

Series 2

Released September 16, 2016 - The ‘Series 2’ was released alongside the ‘Series 1’ and brought with it a 2x brighter screen, vastly improved water resistance and a GPS module. This ultimately improved it’s ability to perform fitness-related tasks. [Fitness Release]

  • OLED Retina display (2nd Generation, 1000 nits brightness)
  • Water resistance up to 50 meters
  • Apple S2 SiP
  • Larger Taptic Engine
  • Speaker pump (to remove water from speakers)
  • Edition: Ceramic

Series 3

Released September 22, 2017 - The ‘Series 3’ introduced LTE cellular models as well as a barometric sensor and even more-improved processor. [Connectivity Release]

  • LTE cellular
  • Barometric altimeter sensor
  • Improved processor (Siri can now audibly speak)
  • Apple S3 SiP
  • Bluetooth 4.2
  • 16 GB onboard storage
  • 768MB RAM
  • LTE models Digital Crown featured a big red dot
  • Ceramic sensor housing/back of device

Series 4 *

Released September 21, 2018 - The ‘Series 4’ introduced larger, rounded, edge-to-edge screens as well as the ability to perform electrocardiogram (ECG) measurements. An improved accelerometer and gyroscope brought “fall detection” to the device. [Health Release]

  • Display sizes 40mm and 44mm
  • ECG
  • Fall detection via improved accelerometer and gyroscope
  • LTPO OLED Retina display
  • Apple 64-bit S4 SiP
  • Bluetooth 5.0
  • Microphone moved to support better call quality
  • Haptic feedback in Digital Crown
  • 1 GB RAM
  • New 2nd generation heart rate sensor
  • Cellular models now sport a more-subtle red ring on Digital Crown
  • W3 wireless chip
  • Edition: NONE Available

Series 5

Released September 20 2019 - The ‘Series 5’ brought a much requested feature in the “always-on display” as well as a Magnetometer/compass.

  • Always on display
  • Magnetometer w/ compass function
  • Apple S5 SIP
  • Improved ambient light sensor
  • 32 GB onboard storage
  • Edition: Titanium

Series 6

Released September 18, 2020 - The ‘Series 6’ primary focus was the blood oxygen sensor suite supporting Apple’s continued push into health.

  • Blood oxygen sensors (SpO2 / VO2max)
  • Real-time/always on altimeter
  • U1 locator chip
  • Force Touch has been removed from the display
  • Apple S6 SIP
  • Dual-band WiFi
  • Larger Taptic Engine

Series 7

Announced September 14, 2021 - The ‘Series 7’ introduces new structural geometry which supports a larger overall display and a more durable design.

  • Larger display (40% smaller bezels, 20% larger screen)
  • Updated screen geometry (improved crack resistance, 50% thicker front crystal, rounder corners)
  • 70% brighter passive always-on display
  • Dust resistance w/ IP6X certification
  • WR50 water resistance
  • 33% faster charging
  • Edition: Titanium


Currently, I have the Apple Watch series 4 and plan to continue using it rather than upgrade to any of the newer models (Series 5 through the Series 7). The only compelling feature to me in any of these upgrades would be the always-on display but that seems like a pretty trivial feature to spend hundreds of dollars on upgrading for. The Series 7 was a pretty disappointing iterative improvement over the Series 6. So yet again, I wait for the next generation.