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Head to head

Samsung Galaxy Watch Ultra 47mmvsSamsung Galaxy Watch8 Classic 46mm

Released
2025-07-25Samsung Newsroom UK — Galaxy Watch8 series, retrieved 2026-09-13
Security updates until
Not published by the makerSamsung UK — How to update software on Galaxy Watch, retrieved 2026-09-13
Released
2025-07-25Samsung Newsroom UK — Galaxy Watch8 series, retrieved 2026-09-13
Price
£449Samsung Newsroom UK — Galaxy Watch8 series, retrieved 2026-09-13
Security updates until
Not published by the makerSamsung UK — How to update software on Galaxy Watch, retrieved 2026-09-13

1 win for Galaxy Watch Ultra 47mm0 wins for Galaxy Watch8 Classic 46mm1 gap borderline1 difference you won’t notice

Verdict: Galaxy Watch Ultra 47mm ahead on 1 row, Galaxy Watch8 Classic 46mm on none

On the makers’ published figures, the Galaxy Watch Ultra 47mm wins on battery life (maker's claim) (80 h against 40 h). One gap is borderline, a difference most people would not notice: case size (47 mm against 46 mm). The difference in weight (case only) is below the threshold you would notice. Both state the same peak brightness. The other 25 rows have no threshold or no direction to judge by, so nobody wins them.

True to scale

Galaxy Watch Ultra 47mm · 47.4 × 47.1 mmGalaxy Watch8 Classic 46mm · 46.4 × 46 mm

Case outlines from each maker’s published dimensions, drawn to scale. A round case is an ellipse at those figures.

Specifications

A win is marked only where the figures can be ranked and the gap is one you could notice on the wrist. A row the site has no threshold for says whether the two differ, and that it is not ranking them. = marks the same figure on both, ≠ not ranked a difference with no ranking. Every figure carries its source.

Body

SpecificationSamsung Galaxy Watch Ultra 47mmSamsung Galaxy Watch8 Classic 46mm
DimensionsDiffers, but not ranked.
47.4 x 47.1 x 12.1 mmOfficial
46.4 x 46 x 10.6 mmOfficial
Case size
47mmOfficial
46mmOfficial

Marginal — most people won’t notice.

Case shapeSame.
roundOfficial
roundOfficial
Weight (case only)
60.5gOfficial
63.5gOfficial

You won’t notice this difference.

Case materialDiffers, but not ranked.
TitaniumOfficial
Stainless SteelOfficial
Water ratingDiffers, but not ranked.
10 ATM + IP68 + MIL-STD-810HOfficial
5 ATM + IP68 / MIL-STD-810HOfficial

Display

SpecificationSamsung Galaxy Watch Ultra 47mmSamsung Galaxy Watch8 Classic 46mm
Display typeSame.
Super AMOLED, Full Colour Always On DisplayOfficial
Super AMOLED, Full Colour Always On DisplayOfficial
Display sizeDiffers, but not ranked.
1.47inOfficial
1.34inOfficial
ResolutionDiffers, but not ranked.
480 x 480Official
438 x 438Official
Peak brightnessSame.
3000nitsOfficial
3000nitsOfficial
Always-on displaySame.
YesOfficial
YesOfficial

Platform

SpecificationSamsung Galaxy Watch Ultra 47mmSamsung Galaxy Watch8 Classic 46mm
Operating systemSame.
Wear OS 6Official
Wear OS 6Official
ChipSame.
Exynos W1000 (5 core, 3nm)Official
Exynos W1000 (5 core, 3nm)Official
StorageSame.
64GBOfficial
64GBOfficial
RAM
No verified data
2GB3rd party

Battery

SpecificationSamsung Galaxy Watch Ultra 47mmSamsung Galaxy Watch8 Classic 46mm
Battery life (maker's claim)
80hOfficialwins this row
40hOfficial

Galaxy Watch Ultra 47mm is ahead here, by a gap you’d notice.

Battery capacity
No verified data
445mAhOfficial

Samsung UK — Galaxy Watch8 Classic 46mm specs claims 445 mAh · GSMArena reports 445 mAh

ChargingSame.
Fast Charging (WPC-based wireless charging)Official
Fast Charging (WPC-based wireless charging)Official

Health

SpecificationSamsung Galaxy Watch Ultra 47mmSamsung Galaxy Watch8 Classic 46mm
SensorsSame.
Samsung BioActive Sensor (Optical Bio-signal Sensor + Electrical Heart Signal + Bioelectrical Impedance Analysis), Temperature Sensor, Accelerometer, Barometer, Gyro Sensor, Geomagnetic Sensor, Light Sensor, 3D Hall sensorOfficial
Samsung BioActive Sensor (Optical Bio-signal Sensor + Electrical Heart Signal + Bioelectrical Impedance Analysis), Temperature Sensor, Accelerometer, Barometer, Gyro Sensor, Geomagnetic Sensor, Light Sensor, 3D Hall sensorOfficial
ECGSame.
YesOfficial
YesOfficial
Skin temperatureSame.
YesOfficial
YesOfficial
GPSSame.
L1+L5 Dual-Frequency GPS (GPS, Glonass, Beidou, Galileo)Official
L1+L5 Dual-Frequency GPS (GPS, Glonass, Beidou, Galileo)Official

Connectivity

SpecificationSamsung Galaxy Watch Ultra 47mmSamsung Galaxy Watch8 Classic 46mm
Cellular modelSame.
YesOfficial
YesOfficial
Cellular model priceDiffers, but not ranked.
£599Official
£499Official
UK networks with eSIMSame.
EE, Vodafone3rd party
EE, Vodafone3rd party
BluetoothSame.
5.3Official
5.3Official
NFC paymentsSame.
YesOfficial
YesOfficial

Compatibility

SpecificationSamsung Galaxy Watch Ultra 47mmSamsung Galaxy Watch8 Classic 46mm
Works withSame.
Android 11.0 or higher and with more than 1.5GB of memoryOfficial
Android 11.0 or higher and with more than 1.5GB of memoryOfficial
CompatibilitySame.
Android; some features need a Samsung phoneOfficial
Android; some features need a Samsung phoneOfficial
6 attributes neither watch has a sourced figure for

Strap width · Display area · Charge to 80% · Blood oxygen · Blood pressure · Wi-Fi. Rows appear as sources are cited — a gap in our data, not a statement about either watch.

The pairs a buyer of either watch would also weigh. Any two watches in the catalogue can be compared from the chooser.