Galaxy Watch4 Classic

Whether the watch is on Samsung's list of devices that get security updates. Samsung lists its watches as Quarterly: about one update every three months.

"No longer updated" means the watch is no longer on that list, so new security problems may not be fixed.

Matters most if: You're buying a used watch, or you plan to keep it for years.

What Samsung announced about software updates for its Wear OS watches, in Samsung's words.

In February 2022 Samsung promised up to four years of One UI Watch and Wear OS updates for Galaxy Watch4 and the Galaxy Watch models after it. What Samsung later told the press is shown under the row, never in place of the official promise.

The software the watch came with: Samsung's One UI Watch on top of Wear OS, Google's software for watches.

A watch moves to newer versions through updates, so this shows where it started, not what it runs today.

The phones Samsung says the watch works with. Galaxy Watch4 and later need an Android phone with Google Mobile Services; they do not work with an iPhone.

Some health features also need a Samsung Galaxy phone; the health section says which.

Matters most if: Your phone is not a Samsung Galaxy, or it runs an older version of Android.

Whether the watch can be set up with an iPhone. Samsung's Wear OS watches (Galaxy Watch4 and later) cannot.

Galaxy Watch3 and the older Tizen watches worked with an iPhone when they came out.

Matters most if: You use an iPhone.

The AI features Samsung names for the watch, such as Gemini, Google's assistant, or Energy Score, a daily readiness score.

Samsung says Galaxy AI features need a compatible Galaxy phone, the Samsung Health app and a Samsung account. "Not stated by Samsung" means Samsung's pages for the watch name none.

The main processor: the part that runs apps, workouts and the watch face. Samsung uses its own Exynos chips; Galaxy Watch9 and Galaxy Watch Ultra2 use Qualcomm's Snapdragon Wear Elite Platform.

Apps and workouts start faster on a faster chip. Compare the chip names rather than the year.

Memory (RAM) is the watch's short-term working memory for the apps running right now, measured in GB (gigabytes).

More memory lets the watch keep more apps ready without reloading them.

Space for apps, music and maps saved on the watch, in GB (gigabytes).

Part of it is taken by the watch's own software, so you have less than the figure for your own things.

The lowest US price Samsung announced when the watch came out, before sales tax. Most models start with the smallest Bluetooth version.

This is not what it costs today: check the used links for current prices. If Samsung has not confirmed a price, the site shows "Price not confirmed by Samsung".

Super AMOLED is Samsung's name for its OLED screens, where each pixel makes its own light.

Black parts of the screen are switched off, so a dark watch face shows clearly without lighting the whole screen.

How bright the screen can get at most, in nits (a unit of brightness).

A brighter screen is easier to read in direct sunlight. Samsung says the 5,000 nits of Galaxy Watch Ultra2 is a peak in part of the screen; full-screen brightness may differ.

Samsung's Always On Display keeps the watch face showing when your wrist is down.

Samsung's battery figures are shorter with it on: for Galaxy Watch6 Classic, up to 30 hours with it on and up to 40 hours with it off.

The glass over the screen. Samsung uses Sapphire Crystal on recent models; Galaxy Watch4 used Corning Gorilla Glass.

Samsung says Galaxy Watch5 was its first smartwatch with a Sapphire Crystal display.

The sensors Samsung lists for the watch. The Samsung BioActive Sensor on the back combines three in one chip: an optical heart sensor, an electrical heart sensor (for ECG) and a body composition sensor (bioelectrical impedance analysis).

Which health features you can use also depends on your country and your phone.

More in the glossary →

The battery's capacity in mAh (milliamp-hours), for each case size. For most models Samsung gives the capacity rather than hours of use.

Samsung says actual battery life varies with how you use the watch, the model and the network, so capacity is only a rough guide.

The hours of use Samsung states, for the models it gives a figure for.

Samsung's figures come from its own tests; workouts with GPS and LTE use shorten them.

Samsung's name for how fast the watch charges on its wireless charger.

Samsung gives examples for some models, such as eight minutes of charging covering eight hours of sleep tracking on Galaxy Watch5.

The weight of the watch for each case size, as Samsung gives it.

Samsung weighs its watches without the band, so the watch on your wrist weighs more.

5ATM and 10ATM are water-resistance classes: the pressure of 50 meters and 100 meters of water. Samsung describes 10ATM as up to 100 meters of water for up to 10 minutes.

Samsung says water resistance is not permanent and can diminish over time, and to rinse the watch in fresh water after it has been in seawater.

Matters most if: You swim with your watch.

More in the glossary →

IP68 means dust-tight and water-resistant under water: Samsung says up to 1.5 meters (5 feet) of fresh water for up to 30 minutes. IP69K, on Galaxy Watch Ultra2, adds protection against powerful, hot water jets.

Neither rating makes the watch a diving instrument. Samsung says Galaxy Watch Ultra2 is its first watch certified to EN13319, a standard for diving instruments.

More in the glossary →

MIL-STD-810 is a set of US military test methods, such as heat, cold, drops and dust. Samsung names the version the watch passed: 810G or the newer 810H.

Samsung says real-world use may vary from the test conditions and extreme conditions are not guaranteed.

A ring around the screen that turns, for scrolling through the watch's screens without touching the display. Samsung's Classic models have one.

Watches without it use the touch screen and buttons instead.

How the band attaches, or the band the watch comes with, as Samsung names it. The Dynamic Lug System on Galaxy Watch Ultra, Watch8, Watch8 Classic and Watch9 holds the watch closer to the wrist.

Samsung says it keeps the sensors in place for more reliable health readings. When you buy a new band, check that it lists your watch model.

More in the glossary →

Whether Samsung sells an LTE version, which has its own mobile connection, for calls and data without your phone nearby.

Samsung says the LTE version needs a separate plan from your carrier, and some carriers do not support calls without the phone.

Matters most if: You run or travel without your phone.

Near-field communication: lets you pay by holding the watch near a card reader.

Paying with the watch also needs a payment app and a bank that supports it in your country.

The satellite systems the watch uses to find where you are. "L1+L5 Dual-Frequency" means it listens to two GPS frequencies.

Samsung says Galaxy Watch7 was the first Galaxy smartwatch with dual-frequency GPS, and that LTE models can use GPS without a phone.