Smartwatches compared

The most important question before buying isn't "which watch is best?" but "which watch works with my smartphone?". An Apple Watch works exclusively with an iPhone. Samsung's Galaxy Watch runs Wear OS and pairs with Android phones, although some health features such as ECG or blood pressure calibration require a Samsung Galaxy smartphone. Huawei, Amazfit and Xiaomi use their own apps on Android and iOS, but sometimes offer fewer features on iOS – replying to messages, for example.

The many low-cost models without a well-known brand usually rely on apps such as "Da Fit", "FitCloudPro" or similar. That often works fine for step counting and notifications, but updates and data protection are hard to judge. If your health data matters to you, it's worth checking where the app stores it.

AMOLED displays show vivid colours and deep blacks and allow a power-saving always-on display. LCD screens are cheaper but often harder to read in sunlight. Display size is given in inches; 1.3 to 1.5 inches looks right on most wrists, while square watches of 1.8 inches and more are noticeably bulky.

When it comes to battery life, the more a watch can do, the more often it needs charging. Wear OS and Apple watches typically last one to three days; watches with their own lightweight operating system (Huawei GT series, Amazfit, many unbranded models) often last one to two weeks. GPS tracking and an always-on display shorten battery life noticeably.

Many smartwatches advertise IP67 or IP68. These ratings describe protection against dust and immersion in fresh water under lab conditions, but say nothing about water pressure while swimming front crawl or diving in. For swimming, look for at least 5 ATM and explicit approval for swimming in the manufacturer's specifications, and rinse the watch after salt or chlorinated water. Avoid hot water, soap, saunas and steam rooms with any smartwatch, because heat and surfactants age the seals.