This comparison puts the Apple Watch SE 3 and Apple Watch Series 9 side by side — two smartwatches measured against the same 32-spec sheet, with every meaningful gap scored and explained. On our weighted VS Score the Apple Watch Series 9 finishes ahead, 95 to 71 — a decisive result.
The most consequential difference is blood oxygen (SpO2) — the Apple Watch Series 9 has it, the Apple Watch SE 3 does not. Street prices currently start at $ 219.99 for the Apple Watch SE 3 and $ 306.25 for the Apple Watch Series 9. That is a $ 86.26 premium for the Apple Watch Series 9 — worth keeping in mind as you read the score gaps below.
Tap a category to see which one wins it.
Design
Apple Watch SE 388
Apple Watch Series 975
Apple Watch SE 3 wins Design
Display
Apple Watch SE 30
Apple Watch Series 9100
Apple Watch Series 9 wins Display
Health & fitness
Apple Watch SE 364
Apple Watch Series 9100
Apple Watch Series 9 wins Health & fitness
Battery
Apple Watch SE 3100
Apple Watch Series 9100
This category is a tie
Connectivity
Apple Watch SE 3100
Apple Watch Series 9100
This category is a tie
Software
Apple Watch SE 3100
Apple Watch Series 9100
This category is a tie
71Points
95Points
Where the Apple Watch SE 3 beats the Apple Watch Series 9
15.9 g less weight ?26.4 g vs 42.3 g
Where the Apple Watch Series 9 beats the Apple Watch SE 3
1 mm more case size ?45 mm vs 44 mm
0.12 " more display size ?1.9 " vs 1.78 "
36 px more resolution ?484 px vs 448 px
1,000 nits more peak brightness ?2,000 nits vs 1,000 nits
The spec sheet pulls in both directions. These are the gaps big enough to shape the decision — with the actual figures, and what each one means in real-world use.
Blood oxygen (SpO2)Health & fitness
No vs Yes — only the Apple Watch Series 9 has it
Measures blood-oxygen saturation.
ECGHealth & fitness
No vs Yes — only the Apple Watch Series 9 has it
Takes an electrocardiogram to check heart rhythm.
Peak brightnessDisplay
1,000 nits vs 2,000 nits — 2× more for the Apple Watch Series 9
A brighter screen is easier to read in sunlight.
WeightDesign
26.4 g vs 42.3 g — 38% less for the Apple Watch SE 3
A lighter watch is more comfortable to wear all day.
ResolutionDisplay
448 px vs 484 px — 7% more for the Apple Watch Series 9
A higher pixel count produces sharper text and graphics.
On paper this is a win, but a gap this small is unlikely to be noticeable in daily use.
Which one should you buy?
There is no single answer — it depends on what you will actually use it for. Match your priority to the pick below.
Best for health & fitnessApple Watch Series 9 takes the category 100 to 64 — driven by blood oxygen (SpO2) (No vs Yes).
Best for designApple Watch SE 3 takes the category 88 to 75 — driven by weight (26.4 g vs 42.3 g).
Best for displayApple Watch Series 9 takes the category 100 to 0 — driven by peak brightness (1,000 nits vs 2,000 nits).
On a budgetApple Watch SE 3 is the cheaper way in at $ 219.99, and still scores 71 overall.
The safe all-rounderApple Watch Series 9 wins more of the categories that carry real weight, topping the overall VS Score at 95.
Where each one falls short
Apple Watch SE 3
Blood oxygen (SpO2): No vs Yes
ECG: No vs Yes
Peak brightness: 1,000 nits vs 2,000 nits
1 spec is unreported (shown as Unknown) and excluded from its scores.
Apple Watch Series 9
Weight: 26.4 g vs 42.3 g
1 spec is unreported (shown as Unknown) and excluded from its scores.
What matters to you?
Drag the sliders to weight each category and re-rank the products to suit your priorities.
Design
Display
Health & fitness
Battery
Connectivity
Software
Your ranking
Apple Watch SE 3Your pick72
Apple Watch Series 9Your pick95
Score breakdown
Design
Apple Watch SE 388
Apple Watch Series 975
Decided by weight (26.4 g vs 42.3 g) and case size (44 mm vs 45 mm).
Display
Apple Watch SE 30
Apple Watch Series 9100
Decided by peak brightness (1,000 nits vs 2,000 nits) and resolution (448 px vs 484 px).
Health & fitness
Apple Watch SE 364
Apple Watch Series 9100
Decided by blood oxygen (SpO2) (No vs Yes) and ECG (No vs Yes).
Battery
Apple Watch SE 3100
Apple Watch Series 9100
Connectivity
Apple Watch SE 3100
Apple Watch Series 9100
Software
Apple Watch SE 3100
Apple Watch Series 9100
How the VS Score works — and what it can’t tell you
Every measurable spec is scored relative to this matchup: the best value here earns 100%, the worst 0%, and everything between scales linearly. Each spec then counts according to an editorial weight that reflects real-world impact — a battery-capacity gap moves the score far more than a colour-options list. The category scores above are the weighted results inside each group, and the overall VS Score rolls all of them together; the evidence line under each category names the specs that actually decided it.
Unknown values are never estimated. A spec a product doesn’t report simply drops out of that product’s scoring — it isn’t penalised with a guess — and a spec only one side reports can never produce a “win”. The trade-off is honest but real: a thinner spec sheet means a score built on fewer data points, which is why the completeness figures are disclosed under About this data.
Most importantly: a spec-sheet lead is not the same as a better product. Megapixels, gigahertz and benchmark points describe capacity, not experience — image processing, software optimisation, thermals, haptics and ergonomics decide how a device actually feels, and no table captures reliability or long-term support quality. Treat the scores as a structured summary of what can be measured, read the caveats under each key difference, and use the weight tuner to re-rank the comparison by what matters to you.
Design
Weight ?
26.4 g
42.3 g
A lighter watch is more comfortable to wear all day.
Case size ?
44 mm
45 mm
The case diameter; larger cases fit bigger displays, smaller ones suit slimmer wrists.
Case material ?
Glass front
Sapphire crystal front
The case material (e.g. aluminium, titanium).
Water resistance ?
5 ATM
5 ATM
A higher ATM rating allows swimming and diving.
Always-on display ?
✓Apple Watch SE 3
✓Apple Watch Series 9
Shows the time and stats without raising your wrist.
Sapphire glass ?
✓Apple Watch SE 3
✓Apple Watch Series 9
A scratch-resistant sapphire crystal protects the screen.
Colors ?
Midnight, Starlight
Graphite, Silver, Gold, Red
The case and band colour options the watch is sold in.
Display
Display size ?
1.78 "
1.9 "
A larger display is easier to read and interact with.
Resolution ?
448 px
484 px
A higher pixel count produces sharper text and graphics.
Display type ?
Retina LTPO OLED
Retina LTPO OLED
The screen technology (e.g. AMOLED).
Peak brightness ?
1,000 nits
2,000 nits
A brighter screen is easier to read in sunlight.
Health & fitness
Heart rate monitor ?
✓Apple Watch SE 3
✓Apple Watch Series 9
Continuously tracks your heart rate.
Blood oxygen (SpO2) ?
✗Apple Watch SE 3
✓Apple Watch Series 9
Measures blood-oxygen saturation.
ECG ?
✗Apple Watch SE 3
✓Apple Watch Series 9
Takes an electrocardiogram to check heart rhythm.
Blood pressure ?
✗Apple Watch SE 3
✓Apple Watch Series 9
Estimates blood pressure from the wrist.
Sleep tracking ?
✓Apple Watch SE 3
✓Apple Watch Series 9
Monitors sleep stages and quality.
Built-in GPS ?
✓Apple Watch SE 3
✓Apple Watch Series 9
Tracks routes and distance without a phone.
Skin temperature ?
✓Apple Watch SE 3
✓Apple Watch Series 9
Senses skin temperature for health insights.
Fall detection ?
✓Apple Watch SE 3
✓Apple Watch Series 9
Detects hard falls and can call for help.
Sport modes ?
? Unknown (Apple Watch SE 3)
? Unknown (Apple Watch Series 9)
More tracked workout types suit more activities.
Battery
Battery life ?
18 h
18 h
Estimated hours of use between charges.
Fast charging ?
✓Apple Watch SE 3
✓Apple Watch Series 9
Tops up quickly from empty.
Wireless charging ?
✓Apple Watch SE 3
✓Apple Watch Series 9
Charges on a wireless pad or puck.
Charging time ?
45 min
45 min
How long a full charge takes; lower is better.
Connectivity
Bluetooth version ?
5.3
5.3
A newer Bluetooth version improves range and efficiency.
Wi-Fi ?
✓Apple Watch SE 3
✓Apple Watch Series 9
Connects to Wi-Fi for updates and sync without a phone.
Dual-frequency GPS ?
✗Apple Watch SE 3
✗Apple Watch Series 9
L1+L5 GPS gives more accurate tracking in cities and forests.
LTE / cellular ?
✓Apple Watch SE 3
✓Apple Watch Series 9
Make calls and stream without your phone nearby.
NFC payments ?
✓Apple Watch SE 3
✓Apple Watch Series 9
Pay contactlessly from your wrist.
Speaker & microphone ?
✓Apple Watch SE 3
✓Apple Watch Series 9
Take calls and use a voice assistant on the watch.
Software
Operating system ?
watchOS 26
watchOS 10
The watch software platform.
Onboard storage ?
64 GB
64 GB
More storage holds more offline music and apps.
About this data
Specifications are compiled from each manufacturer’s official spec sheet, cross-checked against trusted specification databases, and normalised into one schema so identical things are compared identically.
Specifications last verified July 8, 2026.
Data completeness: Apple Watch SE 3 97% and Apple Watch Series 9 97% of the 32 specs in this category. Anything we could not verify is shown as Unknown — never estimated — and is excluded from all scores.
Prices and availability come from live retailer feeds via our shopping partners and refresh throughout the day; a missing price means no partner currently lists the product, not that it is discontinued.
Want the full picture? Our editorial guidelines explain how we research products, weight the scores and stay independent.
Spotted an error in a spec? Tell us and we will correct the sheet.
The Apple Watch Series 9 is the clear winner, scoring 95 to 71 on our VS Score. It leads on Display and Health & fitness. The Apple Watch SE 3 answers back with stronger Design. Pick the Apple Watch Series 9 unless Design matters most to you — then the Apple Watch SE 3 is the smarter buy.