スマートウォッチ 比較

How to choose a smartwatch in 2026

The Mars Score for smartwatches weights health sensors (30%), battery (25%), display (20%) and platform fit (25%). Unlike phones, smartwatch choice is gated hard by ecosystem: Apple Watch only pairs with iPhone, Pixel Watch only with Android, Garmin works with both but with reduced notifications on iOS.

Ecosystem comes first, specs second

watchOS gives the deepest iPhone integration. Wear OS 5+ (Pixel Watch, Galaxy Watch) is now mature and matches watchOS on app catalog. Garmin OS and Polar OS prioritize multi-band GPS, training metrics, and 1–4 week battery over apps. HarmonyOS and HyperOS deliver 14+ day battery and excellent health sensors at half the price, but with limited third-party apps. Pick the OS that matches your phone and use-case before comparing specs.

Health sensors: ECG, SpO2, temperature, blood pressure

ECG (has_ecg) is FDA-cleared on Apple Watch, Galaxy Watch, Pixel Watch, and most Withings models — and useful for catching atrial fibrillation. SpO2 (has_spo2) is widespread but accuracy varies wildly between brands. Wrist temperature unlocks cycle tracking and early-illness detection. Blood pressure (Galaxy Watch, Huawei Watch D2) requires monthly calibration against a cuff. Buy the sensor you will actually use, not the longest spec list.

Battery: 18 hours vs 14 days

Apple Watch Series 10 and Galaxy Watch ship 18–40-hour battery. Pixel Watch is similar. Garmin Fenix and Epix Pro deliver 16–28 days in smartwatch mode, 30–60 hours in multi-band GPS. The gap is widening, not closing, because Apple and Google prioritize always-on AMOLED + cellular over runtime. If you backpack, train for ultra distance, or hate daily charging, the answer is Garmin or Polar.

Display: AMOLED vs MIP

AMOLED (Apple, Samsung, Pixel, Garmin Epix, Polar Vantage V3) is gorgeous but eats battery with always-on. Memory-in-Pixel transflective (Garmin Fenix, Forerunner 9xx) is always readable in sunlight and costs almost no battery. Many serious athletes still prefer MIP for that reason.

Multi-band GPS is the new baseline

L1 + L5 multi-band GPS (Apple Watch Ultra 2, Garmin Epix Pro, Coros Vertix 2S) fixes the urban-canyon and dense-tree-cover errors that plagued single-band watches. If you train in cities or forests, this is the spec that matters most.

How vsMars scores smartwatches

Battery and health sensors are weighted heaviest because both compound over years of daily wear. See the public formula on our methodology page, the curated picks on best smartwatches, and detailed comparisons in Mars Labs.