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Technology.

30 August 2021

How to buy the best smartwatch

What features do you need from a smartwatch or Apple Watch and how much should you spend? We explain how to choose the best smartwatch.
CW
Christina Woodger
Smartwatchesadviceguide 460208

The best smartwatches not only look stylish, but will work seamlessly to track fitness, control apps, deliver notifications and help you communicate straight from your wrist. 

In our expert tests we've found plenty of models that tick these boxes, but we've also uncovered smartwatches that are uncomfortable, lack functionality or won’t accurately track your activity.

In this guide, we'll help you to find the perfect smartwatch, whatever your budget. As our tests prove, spending big won't always guarantee you a Which? Best Buy smartwatch.

Just want to see our smartwatch reviews? Discover the best smartwatches.

Video: How to buy the best smartwatch

What is a smartwatch?

A smartwatch is a watch with smart features, bringing features you'd normally use on your smartphone or laptop to your wrist. Many have digital screens but a few 'hybrid' watches have traditional analogue faces and hidden smart features. 

You'll need a smartphone before you can use a smartwatch, as your smartwatch will need to be paired to a phone. You'll need to install the watch's companion app on your phone before you begin. Through the app, you'll be able to control the settings on the watch and view any fitness data it has gathered. 

How much do I need to pay for a good smartwatch?

Smartwatches cost from around £20 to over £500. We've found good models for a little over £100, and there are a range of Best Buy smartwatches for under £150. In fact, hundreds of pounds have separated our cheapest and most expensive Best Buy smartwatches. 

Paying more could get you features such as advanced activity tracking, premium materials, or perhaps a strap and bezel made of stainless steel or aluminium, rather than plastic. New models, especially from bigger brands, usually command a premium. 

Shop carefully and pick the right model for your needs, and you may be surprised at how little you have to spend.

We put step, distance and heart-rate tracking through tough accuracy tests. Find out each model fares in our guide to the most accurate smartwatches and fitness trackers

Which smartwatches are compatible with my phone?

One of the most important factors to consider when buying a smartwatch is whether it’s compatible with your smartphone, as you’ll need to pair or connect them to access incoming calls, texts, emails and apps. 

Fortunately, cross-compatibility is a lot better than it used to be, but there are still some things to bear in mind.

  • If you're an iPhone user, an Apple Watch will be hands down the best option. Apple Watches don't work well with Android phones, although there are ways to get some limited functionality. If you're not interested in a smartphone, but still want a smartwatch, you could use Apple's new Family Setup feature, whereby multiple Apple Watches can be paired with the same iPhone. 
  • Samsung watches run the Tizen operating system. Just as Apple Watches are best with an iPhone, you're best off with a Samsung-branded phone here. However, you will find good compatibility with other Android brands, and some compatibility with iPhones. 
  • Wear OS is Google's smartwatch operating system, and it's the most versatile. It works fairly seamlessly across all Android brands. iPhone users will have a fairly smooth experience, but will miss out on some features, so it's worth checking reviews before buying. For example, you probably won't be able to respond to messages, via text or using your voice, even if your watch supports it for Android. 

What is a hybrid smartwatch?

Some watches, including many watches running Wear OS, combine classic design with modern tech, hiding their smart features behind a traditional-looking watch face. 

These watches will often have a decent or good set of smart features, but aren't intended for hardcore fitness fans who want accurate, detailed tracking for particular sports. Some, due to their design and materials, are primarily about fashion, and won't really be suitable for wearing at the gym, for example the Michael Kors Access Runway

The Mobvoi Ticwatch Pro 2020 has a good set of fitness-tracking features compared to many hybrid watches, but is still more for people wanting to keep fit and active than people wanting specialist tracking. 

Even if all you're after is a chic-looking watch with a smattering of smart features, it's worth checking our reviews before you buy, as we've found some look cheaper in reality than in their marketing pictures – which is disappointing for the high price, particularly if you're buying it for someone for a present. 

Android (Wear OS), Samsung (Tizen) or Apple (watchOS)?

Wear OS by Google

Wear OS was built to work with Android devices, but offers (more limited) iPhone compatibility too. It's another interface designed to direct messages, calls and diary appointments to your wrist. Previously known as Android Wear 2.0, Wear OS has a host of features including the ability to customise watch faces to retrieve the most important information from your favourite apps, and control over notifications. It can give you greater freedom from your smartphone, as standalone apps will work with any Bluetooth or wi-fi connection, even without your phone nearby.

Pros: Wear OS is well maintained by Google and recent updates have resulted in a far sleeker, more intuitive experience. There's also a wealth of apps available to browse in the Play Store.

Cons: Compatibility with iPhones is limited, quality of some apps is hit and miss.

Get help choosing with our Wear OS smartwatch reviews.

Tizen

Samsung smartwatches run off and operating system called Tizen. Tizen was initially only compatible with Samsung smartphones, but it now works with a range of Android handsets and the iPhone 5 and newer, albeit with limitations. 

Pros: Samsung smartwatches are generally constructed from premium materials and have a good range of fitness features. If you're sporty, something like the Samsung Galaxy Watch Active or Samsung Galaxy Watch Active 2 will be more suitable than most of the Wear OS watches, and they have a fashionable, neutral-looking, unisex design that pairs well with both office wear and sports gear. 

Cons: Apps have historically been more limited on Tizen than on Wear OS, although this is slowly improving, with popular apps such as Spotify, Uber and Nest now available. 

Read all of our in-depth Samsung smartwatch reviews or head over to our guide to the best Samsung smartwatches.

watchOS

Designed to work exclusively with iPhones, Apple’s watchOS offers a touch-based interface that lets you scroll through your contacts, dictate texts and build your own fitness regime. Apple periodically releases new versions of the OS to keep things fresh – and for iPhone users at least, maintains a wide selection of useful and informative apps. Recent developments in particular maintained a strong focus on health, fitness and wellbeing.

Pros: watchOS is simple to use and works well with the iPhone, delivering all the notifications you’d expect and allowing you to customise the look and feel of the interface through apps.

Cons: It’s exclusive to Apple Watches, which are expensive devices, even when we're talking about cheaper Apple Watches like the Apple Watch SE

Browse our Apple Watch reviews.

What features do I need on a smartwatch?

Fitness tracking

All smartwatches can cover the basics, such as step and distance tracking. Most have heart-rate monitors, and an increasing number have built-in GPS, so you can track your running route without taking your phone. Many are also waterproof, which is handy if you want to keep your watch on in the pool (although not many offer detailed swimming metrics). 

At Which? we run all smartwatches through a rigorous test to see just how accurate its exercise-logging capabilities really are. 

Good battery life: Most smartwatches use a rechargeable battery, but how long it lasts varies significantly between models. What features a smartwatch has will also have an impact on battery life – models with a large screen, heart-rate monitor or advanced sensors, for example, are likely to run out of juice quite quickly. And switching on GPS will also drain the battery faster. 

Internal storage: Most good smartwatches should have a reasonable amount of internal memory: look for 4GB or more. This not only allows you to download new apps, but also store music so you can listen to tunes without a smartphone in tow.

Wi-fi connectivity: A smartwatch with wi-fi can connect to local networks, so you can continue to receive notifications and use online functions even if your phone is out of Bluetooth range, so long as both your watch and phone have access to a wi-fi network. 

NFC (near-field communication): If you're looking to make contactless payments via your smartwatch, make sure it has built in NFC (near-field communication). Also make sure you bank is compatible. 

Built-in GPS: Most smartwatches will be able to use the GPS on your smartphone. If you like to exercise outside and don’t want to be tied to the GPS on your smartphone, though, built-in GPS is the feature to look for. This will let you track your route and distance while leaving your smartphone safely at home.

Accuracy: We put every smartwatch through the same tests as fitness and activity trackers, including checking the accuracy of step and calorie count, distance travelled, and the built-in heart-rate monitor. 

We know consistency is important too – if a smartwatch is accurate on some days but not on others it will be difficult to track improvements in your fitness levels. We repeat our walking test to see if the smartwatches consistently overstate, understate or hit the accuracy mark.

Waterproofing: Most smartwatches should be at least splash proof, and ideally IP67 or IP68-certified for immersion in water. Note that this doesn't meant the watch is suitable for swimming; this capability is usually measured in atmospheres (ATM). For example, 5 ATM means a smartwatch is water resistant up to a depth of 50 metres.

Built-in heart-rate monitor: Measuring your heart-rate is one of the best ways to track improvements in your fitness levels, as well as being a useful metric for those looking to burn fat. The best smartwatches for fitness will measure your heart-rate all day, as well as telling you when you’ve reached your active heart-rate zone during exercise. Some will even measure the time it takes for your heart-rate to return to a resting rate after exercise, which is indicative of your fitness.

4G connectivity: Also known as cellular connectivity and LTE. This allows you to make and receive calls, texts and other notifications without your phone nearby. It's not available for everyone, as only a small number of network carriers offer LTE. Connectivity will also have a large impact on the battery life of the watch. And you'll need to consider the ongoing monthly cost. 

Built-in speaker: Most smartwatches have a built-in microphone (useful for dictating voice messages as responses, or using a voice assistant to issue commands), but it's less common to find a speaker. This won't be essential for everyone, but if you aspire to make phone calls using just your watch, it's a must have. It's also useful for alarms and reminders as an alternative to the vibration alert.

22mm watch strap: Some smartwatches (including the Apple Watch and older Samsung Gear watches) use a proprietary strap connection, which means you'll have to stick to fairly limited set of branded replacements (or passable imitations). Choose a smartwatch with a removable 22mm watch strap, and you'll find a massive range of designs and materials available, with prices starting from just a few pounds.

Best overall smartwatches

The smartwatches we've picked out below are our top-scoring models overall, assessed across parameters such as how they perform when it comes to notifications and smart features, how accurately they track your fitness, how long it takes to fully charge your device and how much battery life you can expect to get and whether they have clear and reactive screens. 

That's not to say each model here is the absolute best in every way, but these perform well enough in all tests to be our best smartwatches overall. 

  • 83%
    £179.70

    If you can’t exercise without motivational tunes, but also hate running with your smartphone, this is a great option. It tracks heart rate, steps and GPS-based distance accurately too.

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  • 82%
    £207.04

    An excellent choice if you’re after a chunky, rugged-looking smartwatch that can accurately track your exercise over a wide range of different sporting activities. Be aware that its smart features are fairly limited, though.

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Best smartwatches for accurate step counting

Walking is a super-easy form of exercise – and it's free. If you not a fan of more intense exercise aiming for a daily step target is a good, gentle way to build up your fitness. Any smartwatch will record your step count, but whether it does it accurately or not is another matter. 

The smartwatches below aren't the best on test overall, but they're the best ones if your main concern is step tracking. They track steps accurately both during walks and runs and during everyday household activities.

We've only included cheaper models here. There are more expensive watches that track steps accurately, but if this is your main concern you needn't pay extra for features you won't use. 

  • 79%
    £69.00

    A good-looking smartwatch with GPS (so no need to take your phone out running with you), accurate heart-rate monitoring, steps and distance tracking and a wide range of other sports features. Its screen doesn't scratch easily, either. Be aware it's difficult for Android 10 users to set up, though.

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  • 78%
    £158.99

    This smartwatch has a raft of features, including tracking for running, walking, cycling, swimming, yoga, golf and skiing. It's a few years old, so it's cheaper than newer models from this brand. It tracks steps and distance very accurately. If you're prepared to pay more, there's also a version with more advanced music functionality.

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  • 73%
    £69.99

    Not many good smartwatches are available for under £100, but this is one. It has a great screen, it's easy to use, and it tracks common metrics like steps, distance and calorie burn accurately. It's water-resistant to 5ATM (so you can keep it on while swimming) and it offers VO2 max estimates. Ideal if you're into sports.

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How do we test step-tracking accuracy? 

We test how accurately smartwatches log steps during walks and runs, and during household activities, including packing and unpacking the dishwasher, sweeping the floor, going up and down stairs and sitting reading a magazine. 

Some smartwatches wildly overstate or understate step count, missing steps or being so sensitive that they clock up too many. In particular, many smartwatches miscalculate steps during everyday household activities, mistaking any hand movement for you swinging your arm while taking a step. 

Some smartwatches from well-known brands have been out by around 80% in this part of our test.

For more on accuracy, check out our guide to the most accurate smartwatches and fitness trackers

Best smartwatches with heart rate monitors

If you're worried about your heart health, you should speak to your GP. If you're generally healthy and more casually interested in monitoring your heart rate with a view to getting more out of your workouts, then look for a smartwatch with an in-built heart rate monitor. 

By keeping an eye on your heart rate, you can check that you're pushing yourself hard enough during exercise and recovering enough afterwards. 

Monitoring heart rate patterns long term can help you spot things that are causing spikes in your day to day life, and motivate you to take a more active interest in your cardiovascular health.

Some watches go much further, allowing you to take ECGs (electrocardiograms) to check for signs of A-Fib (atrial fibrillation). It's important to note that these aren't medical devices – they're more like toys for the worried well. But you can flag anything unusual with your GP and can help you build a more detailed overall picture of your health. 

  • 82%
    £145.27

    We were really impressed by this smartwatch. It tracks many things accurately, it's easy to use and it comes with a host of useful features, such as in-built GPS, various exercise modes for different sports and the ability to reply to messages using pre-set responses. It feels well-built, too.

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  • 81%
    £259.00

    A really impressive smartwatch. Its built-in GPS and impressive list of features are likely to appeal to serious sports enthusiasts wanting to track their activities. It uses innovative battery technology, too.

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  • 80%
    £289.00

    This good looking watch has plenty of smart and fitness-tracking features. It generally tracks activities well, although it's not the most accurate watch for logging steps around the home, if that's something you're interested in.

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  • 78%
    £389.00

    This watch looks beautiful. It's packed with features, including heart rate monitoring, and tracks metrics like heart rate and distance accurately. However, it was as much as 30% out when tracking steps during household tasks, and its battery life is still annoyingly short.

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How do we test heart-rate tracking accuracy? 

We test smartwatches during low intensity exercise, high intensity running and cycling, and while resting, to see how accurately each one can monitor heart rate. We compare these results to those taken by chest belts, which are known to be much more accurate. 

Again, we see big differences in how accurately smartwatches measure heart rate. 

Some, for example, track accurately during high-intensity exercise but really struggle during low intensity exercise or at rest. One smartwatch we tested from a popular brand was more than 60% out when measuring heart rate at rest. 

Best GPS smartwatches for running

Not all smartwatches have built-in GPS. Some have to rely on your phone's GPS, meaning you'll need to take your phone out with you when you for a run if you want it to track your route and distance. If you leave your phone behind, your distance will be based on step count. 

If you're a keen runner, we recommend looking for a watch with in-built GPS, as GPS-based distance calculations are often (although not always) more accurate than those based on step count alone. 

Be aware that GPS will drain your battery faster, though. 

  • 83%
    £179.70

    If you can’t exercise without motivational tunes, but also hate running with your smartphone, this is a great option. It tracks heart rate, steps and GPS-based distance accurately too.

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    First month only £5, then £9.99 per month, cancel any time

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  • 81%
    £259.00

    A really impressive smartwatch. Its built-in GPS and impressive list of features are likely to appeal to serious sports enthusiasts wanting to track their activities. It uses innovative battery technology, too.

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How we test smartwatches for distance accuracy

All smartwatches are taken on runs and walks along routes of a known length, to see how accurately they can track your distance travelled. Our routes include woods with dense tree coverage. 

Best waterproof smartwatches for swimming

Some smartwatches shouldn't be used in the water at all. Others can be if you've got the right sort of strap, usually silicone. 

Some waterproof watches don't actually give you much in the way of swim-tracking data, but some go into plenty of detail. Some give you lots of useful information such as:

  • number of lengths
  • pace
  • stroke rate
  • stroke detection - whether you're doing front crawl, breast stroke or butterfly, say
  • distance
  • duration
  • calories burned
  • SWOLF - a measure of your swimming efficiency

Many can't give you heart-rate data in swim-mode, but a few can be paired with a heart-rate monitor chest strap. 

Here are some of the most detailed smartwatches for swimming. 

  • 81%
    £369.00

    A terrific smartwatch that’s packed with fitness and smart features, making it a great choice for serious sports enthusiasts wanting to monitor their activities. It offers plenty of stats for keen swimmers, too. Be aware that, although it's a Best Buy for Android phone users, we had difficulties using it on iOS.

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  • 75%
    £267.05

    A great smartwatch for those wanting to track their sports and fitness activities in detail and in particular for those who want to swim or take part in triathlons. It has plenty of good features, including a heart-rate monitor, altimeter and barometer, and a huge range of pre-programmed activities.

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  • 65%
    £261.99

    A rugged, durable watch that makes a good choice for hardcore sportspeople; not really suitable for ordinary folks looking for smart features or wanting to monitor their health and fitness in a more casual way. It tracks distance and number of strokes during swimming accurately, but is sometimes off when tracking pace.

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Water ratings explained

You'll sometimes see wearables' ability to withstand water described according to different ratings. Ingress Protection (IP) ratings are set by the International Electrotechnical Commission (IEC), and refer to the protection provided by the casing of an electrical device in fresh water. 

The first digit after the IP reflects the level of protection against solids, such as dust or grit. The second represents the protection against moisture. An IP code with an X in place of either number means the device hasn't been tested for that element. 

For example, a smartwatch with a rating of IPX7 has been tested for moisture protection, but has not been tested for dust.  

IP code
Level of protection
0
No protection
1-3
Protection against light rain
4-6
Splash proof
7
Protected from immersion in water at a depth of up to 1 metre for up to 30 minutes
8
Protected from continuous immersion in water at a depth of more than 1 metre

You can also look for a water pressure rating. These are standards set by the International Organisation for Standardisation (ISO). 

Pressure tests are measured in atmospheres (ATMs) and replicate the level of pressure at certain depths of water.

Water ratings
Level of protection
1 ATM
Resistant to pressure equivalent to a depth of 10 metres. Splash proof but not shower or swim proof.
3 ATM
Resistant to pressure equivalent to a depth of 30 metres. Splash proof and shower proof and should be fine if accidentally submerged in water. Not designed for swimming.
5 ATM
Resistant to pressure equivalent to a depth of 50 metres. Splash proof, shower proof, can be worn swimming and snorkelling in shallow water.
10 ATM
Resistant to pressure equivalent to a depth of 100 metres. Splash proof, shower proof and suitable for swimming and snorkelling. Not designed for deep water diving or water sports. 
20 ATM
Resistant to pressure equivalent to a depth of 200 metres. Splash proof, showerproof and suitable for swimming and snorkelling. Suitable for surface diving and water sports but not deep water diving.

Put your smartwatch to the test tracking progress in a home gym – our exercise equipment buying guide can help you get started.