Apple Watch Series 4 review

September 2018 saw the launch of Apple’s newest wearable, and the news that the Apple Watch Series 3 would be followed by… the Series 4. No surprises there. But the design, features and specs list of the new product contained plenty of interesting revelations.

The Series 4 has a new design, with (among other changes) a larger screen, flatter body, nicer dial and louder speaker; it’s faster; it can now detect falls and a wide variety of unusual heart activity, and can show twice as many onscreen complications.

It sounds good, but does it justify the higher price tag? In our Apple Watch Series 4 review (which was primarily based on a 40mm sample) we put it to the test. For a direct comparison of this watch with its predecessor, see Apple Watch Series 4 vs Series 3. And if you’re wondering about the next generation, read Apple Watch Series 5 rumours.

Apple Watch Series 4: Price & Availability

The Series 4 is priced from £399/$399 (with GPS only; prices start at £499/$499 with cellular). That’s pretty steep, considering that the Series 3 started at £329/$329 and has since had a price cut to £279/$279, but as we’ll see there are plenty of improvements.

You can buy from Apple or from various networks and resellers such as EE, Vodafone and Currys PC World. Read our best Apple Watch deals roundup for advice on the best places to buy.

Here’s the full line-up in terms of materials, sizes and connectivity. You’ll also get colour choices (including a new and very smart gold steel option), but they never affect the price.

Material Strap 40mm, GPS 44mm, GPS 40mm, cellular 44mm, cellular Buy link
Aluminium Sport Band £399/$399 £429/$429 £499/$499 £529/$529 Apple Store
Aluminium Sport Loop £399/$399 £429/$429 £499/$499 £529/$529 Apple Store
Aluminium Nike Sport Band £399/$399 £429/$429 £499/$499 £529/$529 Apple Store
Aluminium Nike Sport Loop £399/$399 £429/$429 £499/$499 £529/$529 Apple Store
Steel Sport Band n/a n/a £699/$699 £749/$749 Apple Store
Steel Sport Loop n/a n/a £699/$699 £749/$749 Apple Store
Steel Milanese Loop n/a n/a £799/$799 £849/$849 Apple Store
Steel Hermes Leather Single n/a n/a £1,249/$1,249 £1,299/$1,299 Apple Store
Steel Hermes Leather Double n/a n/a £1,399/$1,399 n/a Apple Store
Steel Hermes Leather Rallye n/a n/a n/a £1,399/$1,399 Apple Store
Steel Hermes Leather Deployment Buckle n/a n/a n/a £1,499/$1,499 Apple Store

Apple Watch Series 4: Design & Build Quality

The first three generations of Apple Watch had the same physical chassis. The Series 4 marks the first time Apple has tinkered with this (very attractive) design.

Most fundamentally, the size has changed. Whereas the Series 3 comes in 38mm and 42mm cases (these measurements indicate the length of the watch body from top to bottom, and are not related to the screen size), the 4 comes in 40mm and 44mm. So they take up a little more area on your wrist – and you get more value for that area because the bezels around the screen have been slimmed down. We’ll talk in detail about the screen in a moment.

Apple Watch Series 4 review: Design

But the new watches are flatter too, so the volume of each version is no larger than its older equivalent. The Series 4 is 10.7mm thick, down from the 3’s 11.4mm – so just three-quarters of a millimetre has been shaved off. Is that noticeable? It feels like it is, and a random sample of colleagues shown two wrists with two watches all correctly named the thicker model.

There have been some other, less obvious changes to the physical design. The Digital Crown dial offers (optional) haptic feedback as it’s turned, which is more satisfying and possibly even more accurate to use; the old dial feels lightweight and floaty in comparison. The side button has a lower profile – it’s now flush with the side of the case rather than raised a millimetre or so above it – which we find more attractive without being any harder to find without looking, since you orient by the position of the dial, not by seeking out the raised button.

Apple Watch Series 4 review: Digital Crown

The back is now entirely made of ceramic and sapphire crystal in order to improve cellular signal. The speaker apertures have got bigger, and the microphone hole has moved from left to right. (We discuss audio quality later on.)

There’s a lot going on. Nevertheless, the overall aesthetic is not radically different. The body is still the same iconic squarish rectangle with rounded corners, dial and side button on the right, and brushed-metal finish around the rim. Without that older model for comparison you’ll probably find that people don’t realise it’s the new one at all.

This is about slimming down and reconfiguring, about revising what was a strong design in the first place, rather than rethinking it from the ground up.

Apple Watch Series 4: Specs & Features

The externals have been primped and tweaked, but Apple hasn’t neglected the inside. Here are the highlights of the specs and feature lists.


The screen now fills far more of the watch chassis than before, partly thanks to the shrinking of the bezels and partly thanks to the screen having curved corners to match the case. It’s the same methods used towards the same end as in 2017’s iPhone X redesign: it’s all about removing everything that isn’t screen.

To get technical, we’ve gone from a 272 x 340 or 312 x 390 screen in the Series 3 to a 324 x 394 or 368 x 448 in the 4. And the area of the screens has gone from 563 sq mm and 740 sq mm to 759 sq mm and 977 sq mm: increases of 35% and 32% respectively.

Apple Watch Series 4 review: Screen size comparison

We’ve found that the larger screen means that migrating from a 42mm Series 3 (or earlier) to a 40mm Series 4 works terrifically. You get a screen that’s a little larger within a body that’s smaller, thinner and lighter.

Apple has released a new Infograph watch face specially designed to make the most of the new bigger screens: it has an astonishing eight complications. Whether you can really get your head around quite that much information is another matter.

Apple Watch Series 4 review: Infograph face

Infograph is unavailable on older models, but it’s worth noting that the other new faces demonstrated at the Series 4’s launch (liquid metal, fire and water, Breathe) are not exclusive to that model.


The Series 4 features an Apple-designed S4 dual-core processor chip, which in itself tells us very little: previous generations had an S3, an S2 and so on. Apple claims the S4 is “up to” twice as fast as the (also dual-core) S3, but because there are no benchmarks on watchOS it’s hard to test this scientifically.

Subjectively, it feels quicker. The Activity complication stats take under five seconds to load, whereas our Series 3 takes three times as long; apps start up instantly; swiping from face to face is seamless. There’s no frustrating gap between deciding to do something and it happening.

When starting from a full power off, the Series 4 took 34 seconds to reach the passcode screen. That’s actually really good for an Apple Watch; for comparison, our (year-old) Series 3 took 1m 29s.

(Going further back, as shown in this YouTube video, our Series 2 took 1m 24s when it was brand-new and an 18-month-old original Apple Watch needed more than two minutes.)

Fall detection

As part of this year’s ‘health guardian’ theme, Apple unveiled a new watch feature which detects when you’ve had a fall, waits to see if you get back up again, and sets up an emergency SOS call if you don’t. (Note that the feature is disabled by default for users under the age of 65. Open the Watch app and scroll down to Emergency SOS, and you’ll be able to turn it on.)

Health and safety features need to be there for you in a crisis, and it’s not easy to emulate a crisis in the calm of a testing lab. But naturally we’ve thrown ourselves to the floor several times (and then lain motionless as long as we could bear) to see what happened.

Out of six ‘falls’, two resulted in a warning after about 10 seconds of stillness and an offer to place an emergency call. (It’s easy to decline this, and you can give the system more feedback by specifying whether you didn’t fall at all, or if you did but you’re now okay.) We’re not sure why the other four didn’t trigger the feature.

Apple Watch Series 4 review: Fall detection

This 33% success rate may mean that the system is not to be depended upon – but then again, it may not. A huge part of Apple’s pitch was that the watch can distinguish a real fall from other actions based on subtle biomechanical tells (arm movement is the giveaway, apparently), and it’s entirely possible that our fake dives were not convincing. Maybe the watch is being cleverer than we realise.

Funnily enough we were expecting the opposite problem, since activating the feature brings up a warning that you should expect false positives if you lead an active lifestyle. We’ve not had any of those so far, which perhaps tells its own story.

For more on this, here’s how to use fall detection on an Apple Watch.

Heart monitoring

The Series 4 is a lot more sophisticated at monitoring your heart activity than previous models. It adds an electronic heart sensor to the optical one offered in the Series 3 and earlier, and its own optical sensor is now a second-gen version.

Apple Watch Series 4 review: Heart sensor

Whereas the 3 could warn you about elevated heart rates, the 4 also looks out for low and irregular activity.

When comparing data from the same running workout performed with the Series 4 and an older model (the Series 2, which has the same heart monitor as the Series 3) we noticed that the heart rate graph with the new hardware looked smoother and less gappy, which suggests a more accurate reading – or at any rate a more consistent one.

Apple Watch Series 4 review: Heart monitoring

Note however that the smoothing effect is exaggerated visually because the Series 2’s graph is more zoomed in, covering 144 to 177 rather than 102 to 177. It looks like the Series 2 also takes longer to start picking up a heart rate at the start of the run, which means it doesn’t take account for the low early rates when calculating averages and plotting the final graph.

The Series 4 will also be capable of acting as a portable ECG but this feature is not yet available.

Battery life

Apple says battery life for the Series 4 is the same as for its predecessor, claiming 18 hours as before.

Maintaining the same performance wouldn’t be bad going, given that the new watches have larger screens and thinner bodies. But our experience suggests that while the 18-hour figure probably remains an underestimate, the Series 4 has less battery life than the Series 3 and (particularly) Series 2.

Having been taken off the charger at 7am on day one, the Series 4 lasted until 2pm on the second day. By contrast, the Series 3 made it to 10pm, and the heroic Series 2 made it through the whole second day and eventually died at 1pm on the third day.

  • Series 2: 54 hours (includes two nights)
  • Series 3: 39 hours (includes one night)
  • Series 4: 31 hours (includes one night)

So in the space of two years we’ve gone from two and a half days of use, to just about two days, to a day and a half. That’s still better than the original Apple Watch, which sometimes struggled to make it through a single day if we used it a lot, but seems to be worse than any of the models released since then.

Note that these tests were all run when the devices were brand-new – our faithful old Series 2 doesn’t come close to this performance now – and the devices were powered on but not otherwise being used during the nights (you can eke out a few more hours by powering off during the night even if you can’t get to a charger).

Also bear in mind that battery tests are illustrative, not scientific; your experience could vary hugely depending on your usage. (A long workout on the second day saw a big drop in the Series 4’s battery, for instance, and cellular usage tends to be a killer.)

The Series 4 charges inductively via a small magnetic charging pad. It does so fairly quickly – after half an hour ours went from 0% to 44% – but you’ll tend to be doing it overnight.

Connectivity & Audio

As in the Series 3, the Series 4 is available with or without cellular connectivity, but you pay extra for this and it comes with a number of other drawbacks: battery life will suffer, and your network (assuming it covers the watch at all) will levy an additional fee for data. We’re still not sure the use case is convincing, unless you regularly go jogging and desperately want to stay in touch or stream Apple Music.

Wireless should be improved by the inclusion of a new W3 chip, and Bluetooth has been upgraded to version 5.0 from 4.2 in the Series 3.

The Series 4 comes with GPS as standard, something Apple has offered since the launch of the Series 2. We’ve been hearing reports that GPS performance on the Series 4 is more accurate this year, but can’t say we’ve noticed any noticeable improvements: its reporting of a semi-urban run showed precisely the same approximations and fudges (go round a sharp corner and the watch will track your route in a neat curve instead, passing straight through a block of houses).

Apple Watch Series 4 review: Speaker

As mentioned above the Series 4 has a much improved speaker, whose two apertures are each around twice the size of the ones in the earlier models.

Sure enough we found phone calls and Siri much easier to hear than in the past, and notification noises more clearly noticeable – although haptic feedback is more discreet and you may prefer to use Silent Mode (or just turn down the volume of alerts).

You still can’t play music directly through the onboard speakers; open the Music app and choose a playlist and you’ll be instructed to connect Bluetooth headphones.

Full specs list

  • S4 with 64‑bit dual-core processor
  • W3 wireless chip
  • 16GB storage
  • 324 x 394 or 368 x 448 OLED display with Force Touch, 1,000 nits brightness
  • LTE (cellular models only), GPS
  • 802.11b/g/n 2.4GHz Wi‑Fi
  • Bluetooth 5.0
  • Barometric altimeter
  • Water resistant to 50m, ISO standard 22810:2010
  • Electrical and optical heart sensors
  • 44mm x 38mm x 10.7mm, or 40mm x 34mm x 10.7mm; weight varies according to material

Apple Watch Series 4: Software

The Series 4, like all Apple Watch models, runs watchOS, and version 5 will be preinstalled if you buy now. The device will also be able to install future watchOS updates for free and add further features, security patches, interface tweaks and so on. (You can expect a few years of updates; 2015’s original Apple Watch has only just stopped getting them.)

Like all Apple operating systems, watchOS is a clean and user-friendly platform with a good range of third-party apps. Our experience, however, is that more than any other Apple product the Watch lives and dies by its preinstalled apps, which are excellent: Activity and Workout in particular are the core of a fine fitness companion.

watchOS 5 appears to have improved performance on the watches that are certified to run it (our Series 2 is noticeably faster since updating), but also adds a few interesting features. Your watch will now notice when you exercise and automatically offer to start the appropriate workout; there are competitions in the Activity app; you can customise the layout of Control Centre; and there’s a fun new app called Walkie Talkie.

The Series 4 will be able to install watchOS 6 for free when that is released in autumn 2019.


We’ve been fans of the Apple Watch since the very first version, but most people are not like us. And this is a product line that’s needed to work hard at broadening its appeal.

After the Series 2 (which we adore, but which like many second-gen products got much of its glory by adding features that should have been included in the first place) and the mild disappointment of the Series 3 (which didn’t add much except cellular, an option about which we remain ambivalent), this is a far more substantial upgrade. It’s a refinement which could and should see the Apple Watch crack the mainstream.

There’s the usual yearly speed bump, and the 4 feels slick and smooth to use. And the usual headline features, which in this case focus on health; the improved heart sensors and fall detection are likely to save lives, and an ECG is in the pipeline.

But it’s the physical changes that are most impressive. The screens are far larger without the devices themselves being significantly bigger – they have even been slimmed down for a slightly (but noticeably) lower profile on the wrist. We prefer the new haptic-feedback Digital Crown, and the improved speaker makes phone calls on the watch a practical option. Even the mark to indicate cellular has gone from a ‘look at me’ red blob to a smart but discreet ring.

Shame that battery life seems to have suffered to achieve that slimmer form factor; missing a single night’s charge is likely to cause problems. And this is not a cheap option, even if you wisely give cellular a miss. But overall this is a terrific revamp of an already strong product line: a fine entry point for newcomers with a large budget, or a worthy upgrade, particularly for those on Series 2 or earlier.

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