Only the differences are shown. 7 specs stay the same.
+3you gain
−0you give up
Galaxy Watch4 came out in August 2021. Galaxy Watch Ultra2 came out in August 2026, 5 years later.
Note on Galaxy Watch Ultra2: Withstands -20C to 55C while worn (Samsung lab tests). Trail Run is exclusive to this model. 5,000 nits is a localized peak; Samsung says full-screen brightness may differ. 12% thinner than the previous Ultra.
Updates & compatibility
No longer updated → Quarterly updates
One UI 9 Watch (Wear OS 7), Android 13.0 or higher and with more than 1.5GB of memory, Qualcomm SDW6100 (Penta-Core, 3nm) - Snapdragon Wear Elite Platform, 2 GB RAM +1 more
Display
1.2-inch (40 mm), 1.4-inch (44 mm) → 1.52-inch
Sapphire Crystal
Battery & charging
247 mAh (40 mm), 361 mAh (44 mm) → 800 mAh
Design & durability
40 mm, 44 mm → 47 mm
Titanium, 10ATM, IP69K, MIL-STD-810H
Connectivity
Bluetooth Not stated by Samsung → 6.0
Price check
Galaxy Watch Ultra2 launched at $699.99
All 26 differences
Updates & compatibility3 gains · 3 changes
Security updates
No longer updated (not on Samsung's list)›Quarterly (on Samsung's list)
From Samsung's security updates page, checked on October 16, 2026. Samsung updates watches quarterly at most; it has no monthly list for them. Samsung's security updates page
What does this mean?
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"No longer updated" means the watch is no longer on that list, so new security problems may not be fixed.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.
Software at launch
One UI Watch 3 (Wear OS Powered by Samsung)›One UI 9 Watch (Wear OS 7)
What does this mean?
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.
Phone needed
Android 6.0 or higher and with more than 1.5GB of RAM›Android 13.0 or higher and with more than 1.5GB of memory
What does this mean?
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.
Chip
Exynos W920 Dual Core 1.18GHz (5nm)›Qualcomm SDW6100 (Penta-Core, 3nm) - Snapdragon Wear Elite Platform
What does this mean?
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)
1.5 GB›2 GB
What does this mean?
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.
Storage
16 GB›64 GB
What does this mean?
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.
Update promise
Up to four years of One UI Watch and Wear OS updates (Samsung, February 2022, for Galaxy Watch4 'and upcoming Galaxy Watch series devices'). (same on both)
Galaxy Watch Ultra2: Samsung told the press: five major OS upgrades and five years of security patches (not on a Samsung page as of October 16, 2026).
What does this mean?
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.
Works with iPhone
No (same on both)
What does this mean?
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.
Galaxy AI and Gemini
Not stated by Samsung (for both)
What does this mean?
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.
Price1 change
Price check
Galaxy Watch Ultra2 — launched at $699.99
What your Galaxy Watch4 sells for
- Samsung Trade-In
- Sold listings on eBay
eBay may ask you to sign in to see sold prices.
Links open in a new tab. Prices are set by each seller and change daily.
Starting price
$249.99›$699.99+$450
What does this mean?
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".
Display3 changes · 1 unconfirmed
Display size
1.2-inch (40 mm), 1.4-inch (44 mm)›1.52-inch
Resolution
396 x 396 (40 mm), 450 x 450 (44 mm)›498 x 498
Peak brightness
Not stated by Samsung›5000 nits
What does this mean?
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.
Cover glass
Corning Gorilla Glass with DX+›Sapphire Crystal
What does this mean?
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.
Display type
Super AMOLED (same on both)
What does this mean?
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.
Always On Display
Full Color Always On Display (same on both)
What does this mean?
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.
Health sensors1 unconfirmed
Health features Samsung named at launch: Galaxy Watch4
- Not stated by Samsung
Health features Samsung named at launch: Galaxy Watch Ultra2
- Sleep Apnea feature (needs a Galaxy phone)
- Vitals
- Heart Health Score (needs a Galaxy phone)
- Daily Cardio Load
- Fitness Index
- Hearing
- Trail Run
- Nutrition Alert
Availability varies by country, and some features need a Galaxy phone. Samsung's Health Monitor page
Sensors
Not stated by Samsung›Samsung BioActive Sensor (Optical Bio-signal Sensor + Electrical Heart Signal + Bioelectrical Impedance Analysis), Temperature Sensor, Accelerometer, Barometer, Gyro Sensor, Geomagnetic Sensor, Light Sensor
What does this mean?
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.
Battery & charging1 change · 1 unconfirmed
Battery capacity
247 mAh (40 mm), 361 mAh (44 mm)›800 mAh
What does this mean?
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.
Fast charging
Not stated by Samsung›High-Frequency Fast Charging (WPC-based wireless charging)
What does this mean?
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.
Battery life (Samsung's figure)
Not stated by Samsung (for both)
What does this mean?
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.
Charging
WPC-based wireless charging (same on both)
Design & durability7 changes · 1 unconfirmed
Case sizes
40 mm, 44 mm›47 mm
Case material
Aluminum›Titanium
Weight
25.9 g (40 mm), 30.3 g (44 mm)›61.5 g
Samsung weights are measured without the band.
What does this mean?
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.
Size
40.4 x 39.3 x 9.8 mm (40 mm), 44.4 x 43.3 x 9.8 mm (44 mm)›47.4 x 47.1 x 10.7 mm
Water resistance
5ATM›10ATM
What does this mean?
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.
Dust and water rating
IP68›IP69K
What does this mean?
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.
Military-standard testing
MIL-STD-810G›MIL-STD-810H
What does this mean?
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.
Other certifications
Not stated by Samsung›EN13319, ISO22810 (100 m)
Rotating bezel
None (same on both)
What does this mean?
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.
Extra button
Not stated by Samsung (for both)
Band
Not stated by Samsung (for both)
What does this mean?
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.
Connectivity4 unconfirmed
Bluetooth
Not stated by Samsung›6.0
Wi-Fi
Not stated by Samsung›2.4GHz+5GHz
NFC
Not stated by Samsung›Yes
What does this mean?
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.
GPS
Not stated by Samsung›L1+L5 Dual-Frequency GPS
What does this mean?
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.
LTE model
Yes (same on both)
What does this mean?
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.
What's new
RSS feedAdded Apple Watch vs Galaxy Watch
Compare any Apple Watch with any Galaxy Watch with Wear OS, in Apple's and Samsung's own words. The first row says which phone each watch works with. Only rows where both makers measure the same thing count as a gain or a loss; water ratings, blood pressure features and battery capacity, which Apple does not publish, are shown side by side. You can pick a Galaxy Watch on the Apple Watch tab and an Apple Watch on the Galaxy Watch tab. Galaxy Watch6 and Watch6 Classic now show their US launch prices from Samsung.
Added Samsung Galaxy Watch
Galaxy Watch models with Wear OS, from Galaxy Watch4 (2021) to Galaxy Watch9 and Galaxy Watch Ultra2 (2026), checked against Samsung's own pages only, with a page for each model, comparisons with each other, launch prices from Samsung and model numbers in Find my model. Galaxy Watch3, the other Tizen watches and Gear are on the timeline by year as Legacy. The glossary explains the BioActive Sensor, 5ATM, IP69K and the Dynamic Lug System.
Added Samsung Galaxy Note
Galaxy Note10 and Note20 phones (Note10, Note10+, Note10+ 5G, Note10 Lite, Note20, Note20 5G, Note20 Ultra and Note20 Ultra 5G), checked against Samsung's own pages only, with a page for each model and comparisons with any Galaxy S, iPhone or Pixel. Older Galaxy Note phones, from the first Galaxy Note (2011) to the Galaxy Note9, are on the timeline by year. Galaxy Note and Galaxy S Ultra pages now have an S Pen row.