How to choose a smartwatch that works with your phone

Smartwatches range from simple fitness bands to small computers on your wrist. The right one depends less on the spec sheet and more on your phone, how often you are willing to charge it, and what you will really use it for.

Start with your phone

This one decision rules out half the market. Apple Watch only works with an iPhone. Most Wear OS watches, including Samsung Galaxy Watch and Google Pixel Watch, work best with Android phones, and some features need a phone from the same brand. Garmin, Amazfit, Noise and boAt watches generally work with both, through their own app.

Tip:Search the watch name plus your phone model before buying. Features like ECG, replying to messages or taking calls can depend on the phone, not just the watch.

Decide how often you will charge it

Battery life is the biggest trade-off. Watches with bright screens and lots of apps usually need charging every day or two. Fitness-focused watches can last a week or more. Think honestly about your routine:

• Charge every night anyway? A full smartwatch is fine.
• Want sleep tracking? You need a watch that survives the night, so look for at least two days of battery.
• Travel or trek often? Choose a watch rated for a week or more.

Health sensors: what they do and don’t do

Almost every watch tracks steps, heart rate and sleep. Higher-end models add things like ECG, blood oxygen and skin temperature. These are useful for spotting trends, but they are not medical devices. Treat a worrying reading as a reason to see a doctor, not as a diagnosis.

If you run or cycle, built-in GPS matters more than extra sensors. It lets you track a route without carrying your phone.

Get the size and strap right

Most watches come in two case sizes. The larger one usually has a bigger battery, but it can feel bulky on a small wrist and catch on sleeves. Check the case size in millimetres and the strap length in the listing, and make sure the strap is a standard size you can replace cheaply.

Check water resistance

Ratings like 5 ATM or 50 m mean the watch can handle swimming in a pool. IP68 alone usually means splashes and rain, not swimming. Very few watches are meant for hot showers or saunas, whatever the rating.