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 Series 9

Popular Stories

iPhone SE 4 Vertical Camera Feature

iPhone SE 4 Rumored to Use Same Rear Chassis as iPhone 16

Friday July 19, 2024 7:16 am PDT by
Apple will adopt the same rear chassis manufacturing process for the iPhone SE 4 that it is using for the upcoming standard iPhone 16, claims a new rumor coming out of China. According to the Weibo-based leaker "Fixed Focus Digital," the backplate manufacturing process for the iPhone SE 4 is "exactly the same" as the standard model in Apple's upcoming iPhone 16 lineup, which is expected to...
iPhone 16 Pro Sizes Feature

iPhone 16 Series Is Just Two Months Away: Everything We Know

Monday July 15, 2024 4:44 am PDT by
Apple typically releases its new iPhone series around mid-September, which means we are about two months out from the launch of the iPhone 16. Like the iPhone 15 series, this year's lineup is expected to stick with four models – iPhone 16, iPhone 16 Plus, iPhone 16 Pro, and iPhone 16 Pro Max – although there are plenty of design differences and new features to take into account. To bring ...
bsod

Crowdstrike Says Global IT Outage Impacting Windows PCs, But Mac and Linux Hosts Not Affected

Friday July 19, 2024 3:12 am PDT by
A widespread system failure is currently affecting numerous Windows devices globally, causing critical boot failures across various industries, including banks, rail networks, airlines, retailers, broadcasters, healthcare, and many more sectors. The issue, manifesting as a Blue Screen of Death (BSOD), is preventing computers from starting up properly and forcing them into continuous recovery...
iphone 14 lineup

Cellebrite Unable to Unlock iPhones on iOS 17.4 or Later, Leak Reveals

Thursday July 18, 2024 4:18 am PDT by
Israel-based mobile forensics company Cellebrite is unable to unlock iPhones running iOS 17.4 or later, according to leaked documents verified by 404 Media. The documents provide a rare glimpse into the capabilities of the company's mobile forensics tools and highlight the ongoing security improvements in Apple's latest devices. The leaked "Cellebrite iOS Support Matrix" obtained by 404 Media...
Apple Watch Series 9

2024 Apple Watch Lineup: Key Changes We're Expecting

Tuesday July 16, 2024 7:59 am PDT by
Apple is seemingly planning a rework of the Apple Watch lineup for 2024, according to a range of reports from over the past year. Here's everything we know so far. Apple is expected to continue to offer three different Apple Watch models in five casing sizes, but the various display sizes will allegedly grow by up to 12% and the casings will get taller. Based on all of the latest rumors,...
tinypod apple watch

TinyPod Turns Your Apple Watch Into an iPod

Wednesday July 17, 2024 3:18 pm PDT by
If you have an old Apple Watch and you're not sure what to do with it, a new product called TinyPod might be the answer. Priced at $79, the TinyPod is a silicone case with a built-in scroll wheel that houses the Apple Watch chassis. When an Apple Watch is placed inside the TinyPod, the click wheel on the case is able to be used to scroll through the Apple Watch interface. The feature works...

Top Rated Comments

pbaker103 Avatar
76 months ago
This will be a huge upgrade for me coming from my Series 0
Score: 12 Votes (Like | Disagree)
aolbites Avatar
76 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
76 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
76 months ago
They didnt increase battery life which is sad. Going to wait for series 5.
Score: 6 Votes (Like | Disagree)
johnyslats Avatar
76 months ago
12 hours to go. Hyped!
Score: 6 Votes (Like | Disagree)
Sasparilla Avatar
76 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)