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Head to head

Samsung Galaxy Watch9 40mmvsSamsung Galaxy Watch8 40mm

Released
2026-08-07Samsung Newsroom UK — Galaxy Watch Ultra2 and Watch9, retrieved 2026-09-13
Price
£349Samsung UK store — Galaxy Watch9, 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
£319Samsung 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

0 wins for Galaxy Watch9 40mm0 wins for Galaxy Watch8 40mm1 difference you won’t notice£30 apart at RRP

Verdict: nothing you’d notice between them

On the makers’ published figures, neither the Galaxy Watch9 40mm nor the Galaxy Watch8 40mm wins a row by a gap you would notice. The difference in weight (case only) is below the threshold you would notice. Both state the same case size, peak brightness and battery life (maker's claim). The other 25 rows have no threshold or no direction to judge by, so nobody wins them.

True to scale

Galaxy Watch9 40mm · 42.7 × 40.4 mmGalaxy Watch8 40mm · 42.7 × 40.4 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 Watch9 40mmSamsung Galaxy Watch8 40mm
DimensionsSame.
42.7 x 40.4 x 8.6 mmOfficial
42.7 x 40.4 x 8.6 mmOfficial
Case sizeSame.
40mmOfficial
40mmOfficial
Case shapeSame.
roundOfficial
roundOfficial
Weight (case only)
31.5gOfficial
30gOfficial

You won’t notice this difference.

Case materialSame.
Armor AluminiumOfficial
Armor AluminiumOfficial
Water ratingSame.
5 ATM + IP68 / MIL-STD-810HOfficial
5 ATM + IP68 / MIL-STD-810HOfficial

Display

SpecificationSamsung Galaxy Watch9 40mmSamsung Galaxy Watch8 40mm
Display typeSame.
Super AMOLED, Full Colour Always On DisplayOfficial
Super AMOLED, Full Colour Always On DisplayOfficial
Display sizeSame.
1.34inOfficial
1.34inOfficial
ResolutionSame.
438 x 438Official
438 x 438Official
Peak brightnessSame.
3000nitsOfficial
3000nitsOfficial
Always-on displaySame.
YesOfficial
YesOfficial

Platform

SpecificationSamsung Galaxy Watch9 40mmSamsung Galaxy Watch8 40mm
Operating systemDiffers, but not ranked.
Wear OS 7Official
Wear OS 6Official
ChipDiffers, but not ranked.
Qualcomm SDW6100 (Snapdragon Wear Elite, 3nm, 5 core)Official
Exynos W1000 (5 core, 3nm)Official
StorageSame.
32GBOfficial
32GBOfficial
RAMSame.
2GB3rd party
2GB3rd party

Battery

SpecificationSamsung Galaxy Watch9 40mmSamsung Galaxy Watch8 40mm
Battery life (maker's claim)Same.
40hOfficial
40hOfficial
ChargingDiffers, but not ranked.
Fast ChargingOfficial
Fast Charging (WPC-based wireless charging)Official

Health

SpecificationSamsung Galaxy Watch9 40mmSamsung Galaxy Watch8 40mm
SensorsDiffers, but not ranked.
Accelerometer, Barometer, Bioelectrical Impedance Analysis Sensor, Electrical Heart Sensor, Gyro Sensor, Geomagnetic Sensor, Light Sensor, Optical Heart Rate Sensor, Temperature SensorOfficial
Accelerometer, Barometer, Bioelectrical Impedance Analysis Sensor, Electrical Heart Sensor, Gyro Sensor, Geomagnetic Sensor, Infrared Temperature Sensor, Light Sensor, Optical Heart Rate SensorOfficial
ECGSame.
YesOfficial
YesOfficial
Skin temperatureSame.
YesOfficial
YesOfficial
GPSDiffers, but not ranked.
L1+L5 Dual-Frequency GPS (GPS, Glonass, Beidou, Galileo, QZSS)Official
L1+L5 Dual-Frequency GPS (GPS, Glonass, Beidou, Galileo)Official

Connectivity

SpecificationSamsung Galaxy Watch9 40mmSamsung Galaxy Watch8 40mm
Cellular modelSame.
YesOfficial
YesOfficial
Cellular model priceDiffers, but not ranked.
£399Official
£369Official
UK networks with eSIMSame.
EE, Vodafone3rd party
EE, Vodafone3rd party
Wi-FiSame.
802.11a/b/g/n 2.4GHz+5GHzOfficial
802.11a/b/g/n 2.4GHz+5GHzOfficial
BluetoothDiffers, but not ranked.
6.0Official
5.3Official
NFC paymentsSame.
YesOfficial
YesOfficial

Compatibility

SpecificationSamsung Galaxy Watch9 40mmSamsung Galaxy Watch8 40mm
Works withDiffers, but not ranked.
Android 13.0 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 · Battery capacity · Charge to 80% · Blood oxygen · Blood pressure. 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.