Apple Watch Series 4 vs. Apple Watch Series 3

The all-new Apple Watch Series 4 is just hours from being available for pre-order, with orders opening on Apple.com at 12:01 a.m. PDT on September 14. If you're still on the fence about jumping to the new generation, this post should help you discern all of the pros and cons between sticking with your Apple Watch Series 3 or going with the upgraded Apple Watch Series 4.

Display

Perhaps the first thing you'll notice about the Series 4 is its bigger display, which is up to 35 percent larger than the Series 3. Specifically comparing the larger 42mm Series 3 and 44mm Series 4 models, the Series 3 has a 740 sq mm display area while the Series 4 has a 977 sq mm display area. This means that the 44mm Series 4's display is 32 percent larger than the 42mm Series 3.

apple watch series 4 flames
Likewise for the smaller models, the 38mm Series 3 has a 563 sq mm display area, compared to the 40mm Series 4 with a 759 sq mm display area. This results in a 35 percent display size increase between generations. In essence, this means that the Series 4 packs more screen into what is nearly the same package as the Series 3, with slimmer bezels that are somewhat visually similar to the rounded corners of the iPhone X and iPhone XS.

The increased display area also results in increased resolution, with the 44mm Series 4 including 368x448 pixels, compared to 312x390 on the 42mm Series 3. The 40mm Series 4 has 324x394 pixels, while the 38mm Series 3 has 272x340 pixels. Thanks to all of these changes, app icons and fonts are now bigger and easier to read as well.

Case Size

Although the display sizes have been increased, there are minimal changes to the actual size of the cases for Apple Watch Series 4, despite the new measurements. 38mm in Series 3 and prior has become 40mm, and 42mm in Series 3 and prior has become 44mm, with both of these numbers representing the height of the Apple Watch Series 4 case.

apple watch series 4 vs series 3
This is a change that shouldn't be too noticeable, unless you're comparing the Series 4 with a previous generation model side-by-side. And don't worry about this update affecting your current band collection, as Apple made it clear during yesterday's keynote that all previous Apple Watch bands will fit with the Series 4 case.

apple watch series 3 vs series 4 thick
Looking at the thinness, Apple Watch Series 4 is just under 1mm slimmer compared to Series 3. Series 4 measures in at 10.7mm thin, compared to 11.4mm thin for Series 3.

Processor

apple watch s4As expected with an Apple update, the Series 4 has received a beefed up processor in the form of the 64-bit dual-core S4 processor.

Apple says that this is up to two times faster than the S3 processor found on the Series 3, enabling the Series 4 to be speedier when opening apps and performing other functions.

Watch Faces

Exclusive to Apple Watch Series 4 are a collection of watch faces that take advantage of the enlarged displays to showcase as many as eight complications.

apple watch series4 gold stainless steel 09122018
These complications have been enhanced to be more precise and provide more information, thanks to the increased display area.

apple watch series 4 faces
There are also a few watch faces that will uniquely react to the edges of the Series 4's display, like Vapor, Liquid Metal, and Fire and Water.

Health

For the first time in a wearable device, you'll be able to take a full ECG reading on Apple Watch Series 4. Using electrodes built into the Digital Crown and a new electrical heart rate sensor in the back crystal, an included ECG app will perform a reading when you touch the Digital Crown and hold it for 30 seconds.

apple watch series4 ecg crown 09122018
The app can classify if your heart is beating in a normal pattern or if there are signs of Atrial Fibrillation, which could hint at potential health complications. You'll be able to save your ECG recordings in the iOS Health app and create a PDF to share with your doctor. While Apple Watch has always been able to track your heart rate, the ECG app is a major update to Apple's wearable line.

The ECG app will be added to Apple Watch Series 4 later this year, and will only be available to customers in the United States at launch.

Tidbits

Below you'll find a quick list of features that are new and exclusive to Apple Watch Series 4, which are unavailable on Series 3 and prior devices. We've also listed everything that hasn't changed further down, one notable constant being 18-hour battery life.

Changes between Series 3 and Series 4:

  • Series 4 now includes haptic feedback on the Digital Crown
  • The black ceramic and sapphire crystal back allows radio waves to easily pass through Series 4 for better cellular service
  • The speaker on Series 4 is 50 percent louder
  • Apple has relocated the microphone so that it reduces echo for better sound quality on the receiving end of phone calls
  • With a new accelerometer and gyroscope, Series 4 can detect if you fall down and ask if emergency services should be alerted
  • The improved accelerometer can measure up to 32 g-forces, increased from up to 16 g-forces on Series 3
  • Series 4 has Apple's new W3 wireless chip instead of the previous generation W2
  • Connectivity improvements also include new Bluetooth 5.0, up from 4.2 on Series 3
  • Now all models have 16GB storage capacities, instead of just GPS + Cellular on Series 3
  • Second-generation optical heart sensor

No changes between Series 3 and Series 4:

  • Built-in rechargeable lithium ion battery with an 18-hour battery life
  • GPS, GLONASS, GALILEO, and GZSS
  • LTE and UMTS on GPS + Cellular models
  • 802.11b/g/n 2.4GHz Wi-Fi
  • Barometric altimeter
  • Water resistance up to 50 meters
  • Ambient light sensor
  • Force Touch
  • Display with 1,000 nits brightness
  • Magnetic charging cable and USB power adapter included

If you're interested, Apple Watch Series 4 pre-orders will kick off at 12:01 a.m. PDT on September 14. Our pre-order post can help you figure out when pre-orders go up for you if you're in a different time zone. We also went hands-on with Apple Watch Series 4 after yesterday's "Gather Round" event, which you can read here.

Related Roundup: Apple Watch 10
Buyer's Guide: Apple Watch (Buy Now)

Popular Stories

New Things Your iPhone Can Do in iOS 18

18 New Things Your iPhone Can Do in iOS 18.2

Wednesday November 13, 2024 2:09 am PST by
Apple is set to release iOS 18.2 next month, bringing the second round of Apple Intelligence features to iPhone 15 Pro and iPhone 16 models. This update brings several major advancements to Apple's AI integration, including completely new image generation tools and a range of Visual Intelligence-based enhancements. There are a handful of new non-AI related feature controls incoming as well....
M4 MacBook Pros Thumb

M4 MacBook Pro Uses Quantum Dot Display Technology

Thursday November 14, 2024 4:19 pm PST by
The M4 MacBook Pro models feature quantum dot display technology, according to display analyst Ross Young. Apple used a quantum dot film instead of a red KSF phosphor film, a change that provides more vibrant, accurate color results. Young says that Apple has opted for KSF for prior MacBook Pro models because it doesn't use toxic element cadmium (typical for quantum dot) and is more...
AirPods Crackling Feature

Apple Customers Sue Over Unfixed AirPods Pro Crackling Issue

Wednesday November 13, 2024 11:01 am PST by
A trio of Apple customers this month filed a class action lawsuit against Apple, accusing the Cupertino company of violating California consumer protection laws and false advertising for continuing to sell AirPods Pro models that had ongoing issues with crackling or static sounds. A few months after the AirPods Pro came out in October 2019, buyers began to complain about crackling, rattling, ...
google gemini

Google Releases Standalone Gemini AI App for iPhone

Thursday November 14, 2024 2:54 am PST by
Google has launched its dedicated Gemini artificial intelligence app for iPhone users, expanding beyond the previous limited integration within the main Google app. The standalone app offers enhanced functionality, including support for Gemini Live and iOS-specific features like Dynamic Island integration. The new app allows iPhone users to interact with Google's AI through text or voice...
maxresdefault

M4 Max MacBook Pro: Real-World Usage Tests

Wednesday November 13, 2024 11:59 am PST by
Apple last week replaced the M3 Max MacBook Pro with the new M4 Max MacBook Pro, and we picked up one of the new high-end MacBook Pro machines to see how it compares to the prior model with both benchmarks and real-world tests. We tested an M4 Max with a 16-core CPU, 40-core GPU, and 48GB RAM against an M3 Max MacBook Pro with similar specs. The two machines look similar, but the display on...
iphone passcode green

iOS 18 Security Feature Causes iPhone to Reboot After Three Days of Inactivity

Thursday November 14, 2024 2:19 pm PST by
With iOS 18, Apple introduced a feature that causes the iPhone to reboot every three days, security researchers have confirmed (via TechCrunch). In a demo video, security researcher Jiska Classen proved that an iPhone left untouched for 72 hours will automatically restart, and Graykey manufacturer also Magnet Forensics wrote a blog post about the feature. After a reboot, an iPhone is more...

Top Rated Comments

pbaker103 Avatar
81 months ago
This will be a huge upgrade for me coming from my Series 0
Score: 12 Votes (Like | Disagree)
aolbites Avatar
81 months ago
I'd rather have a thicker case if it meant improved battery life.

Seriously, I mean the Series 4 has 1 hour less talk time than Series 3. It was bad enough when Apple was stagnating, but now it's going backwards.
Score: 7 Votes (Like | Disagree)
snej Avatar
81 months ago
A maybe noteworthy detail is that the Series 4 is still 0.2mm thicker than the Series 1 and 1st generation Apple Watch.
Score: 7 Votes (Like | Disagree)
Agit21 Avatar
81 months ago
They didnt increase battery life which is sad. Going to wait for series 5.
Score: 6 Votes (Like | Disagree)
johnyslats Avatar
81 months ago
12 hours to go. Hyped!
Score: 6 Votes (Like | Disagree)
Sasparilla Avatar
81 months ago
Nice overview, thanks. While the 4 is more capable, for folks that don't have one yet, that 3 starting price point is awesome....the 3 is a great watch.
Score: 4 Votes (Like | Disagree)