Device comparisons
Samsung Galaxy Watch vs Garmin: Sensors Compared
Samsung's Galaxy Watch7 and Watch Ultra offer an FDA-cleared ECG app and cuffless blood pressure estimates that need cuff calibration every 28 days; they pair only with Android. Garmin's Venu 3 and Fenix 8 offer an ECG App in eligible regions and battery measured in weeks. No study compares current Samsung and Garmin heart-rate accuracy.
Devices
Samsung Galaxy Watch (Watch7 / Ultra)
SmartwatchDevice guideGarmin (Venu 3 / Forerunner 965 / Fenix 8)
Sports watchDevice guideSamsung Galaxy Watch7 in green: product photograph from Samsung’s gallery. Garmin fēnix 8 47 mm AMOLED, slate gray case with a black silicone band (part 010-02904-00): product photograph from Garmin.
At a glance
This page does not list head-to-head accuracy numbers, so the scoreboard shows hardware differences only.
| Specification | Samsung Galaxy Watch (Watch7 / Ultra) | Garmin (Venu 3 / Forerunner 965 / Fenix 8) |
|---|---|---|
| BatteryDiffers | 425 / 300 mAh (Watch7 44 / 40 mm); Ultra up to 100 h Power Saving | Up to 14 days (Venu 3); 23 days (FR965); 16 days (Fenix 8 47 mm AMOLED) |
| Water ResistanceDiffers | 5ATM + IP68 (Watch7); 10ATM + IP68 (Ultra) | 5 ATM (Venu 3, FR965); 10 ATM + 40 m dive (Fenix 8) |
| ECGDiffers | ECG Monitor app (FDA K201168) | Venu 3 and Fenix 8: ECG App |
| Blood pressureDiffers | Estimates; calibrate every 28 days | — |
Primary rows only. The study tables further down list more results from the accuracy database.
Hardware specs
| Specification | Samsung Galaxy Watch (Watch7 / Ultra) | Garmin (Venu 3 / Forerunner 965 / Fenix 8) |
|---|---|---|
| BatteryDiffers | 425 / 300 mAh (Watch7 44 / 40 mm); Ultra up to 100 h Power Saving | Up to 14 days (Venu 3); 23 days (FR965); 16 days (Fenix 8 47 mm AMOLED) |
| Water ResistanceDiffers | 5ATM + IP68 (Watch7); 10ATM + IP68 (Ultra) | 5 ATM (Venu 3, FR965); 10 ATM + 40 m dive (Fenix 8) |
| ECGDiffers | ECG Monitor app (FDA K201168) | Venu 3 and Fenix 8: ECG App |
| Blood pressureDiffers | Estimates; calibrate every 28 days | — |
Hardware only. Study results are not repeated in this table. Differs marks values that are not the same. An em dash means this page did not publish that figure.
Specs verified on October 17, 2026: Samsung: Galaxy Watch7 and Watch Ultra compared with previous models, Samsung Support: Galaxy Watch Ultra battery, Samsung Support: blood pressure on Galaxy Watch, Samsung Support: watch and phone compatibility, FDA 510(k) K201168: Samsung ECG Monitor App, Shcherbina et al. 2017, J Pers Med (seven wrist devices), Gillinov et al. 2017, Med Sci Sports Exerc (exercise HR vs ECG, n=50), Miller et al. 2022, Sensors (six devices vs PSG and ECG, n=53), Garmin Venu 3 owner's manual: battery information, Garmin Forerunner 965 owner's manual: battery information, Garmin Fenix 8 owner's manual: battery information, Garmin: ECG App expands to Australia and the EU (Venu 3, Fenix 8).
Pros and cons
Samsung Galaxy Watch (Watch7 / Ultra)
Pros
- ECG Monitor app (FDA K201168)
- Cuff-calibrated blood pressure estimates
- Ultra: 10ATM + IP68; up to 100 h Power Saving
Cons
- Android only
- Blood pressure needs recalibration every 28 days; not for diagnosis
- Older Gear S2 had the highest HR error of seven devices (Shcherbina 2017)
Garmin (Venu 3 / Forerunner 965 / Fenix 8)
Pros
- Up to 14 days (Venu 3), 23 days (FR965), 16 days (Fenix 8 47 mm AMOLED)
- ECG App on Venu 3 and Fenix 8 (regional availability)
Cons
- No blood pressure estimates
- Forerunner 245 overnight HR ICC 0.41 vs ECG (Miller 2022)
What published studies show
One table per metric. These rows come from the accuracy database and are not repeated as a second card list. From the wearable accuracy database (v1.0.0).
Heart rate at rest2 studies
| Device tested | Result | Reference | Sample | Study |
|---|---|---|---|---|
| Samsung Galaxy Watch Active2 | 9.4 bpm (seated rest)Mean absolute error | Holter ECG | n = 23, Rest, sedentary, low- and high-intensity phases | Nissen et al. (2022)Independent |
| Garmin Vivoactive 4 | ρc = 0.9998Lin's concordance correlation | ECG | n = 263, 30-min standardised recording | Theurl et al. (2023)Independent |
Heart rate during exercise7 studies
| Device tested | Result | Reference | Sample | Study |
|---|---|---|---|---|
| Samsung Galaxy Watch Active2squats | 6.1 bpm (squats)Mean absolute error | Holter ECG | n = 23, Rest, sedentary, low- and high-intensity phases | Nissen et al. (2022)Independent |
| Samsung Galaxy Watch 6 | Significantly higher MAE than Apple Watch SE and Verity SenseStudy finding (no single number) | ECG chest strap (Polar H7/ | n = 37, Low/ | Jeong et al. (2026)Independent |
| Samsung Gear S2 | Highest overall error of 7 devicesStudy finding (no single number) | ECG | n = 60, Sitting, walking, running, cycling | Shcherbina et al. (2017)Independent |
| Samsung Galaxy Watch6 | −2.67 bpm (LoA −16.90 to 11.57)Mean bias (signed) | ECG chest strap (Polar H7/ | n = 55, Maximal incremental treadmill test | Inoue et al. (2026)Funding not reported |
More results (2)
| Device tested | Result | Reference | Sample | Study |
|---|---|---|---|---|
| Garmin Vivosmart 5 | Skin pigmentation did not predict error (P = 0.29)Study finding (no single number) | ECG chest strap (Polar H7/ | n = 28, Rest, cycling, recovery | Mulholland et al. (2026)Independent |
| Garmin Fenix 5 | 2.9%–9.2% (range by intensity)Coefficient of variation | ECG chest strap (Polar H7/ | n = 25, Sitting, walking, running, sprints | Düking et al. (2020)Independent |
1 more result in the database. Heart rate accuracy across devices →
Overnight heart rate1 study
| Device tested | Result | Reference | Sample | Study |
|---|---|---|---|---|
| Garmin Forerunner 245 Music | ICC 0.41Intraclass correlation | ECG | n = 53, Overnight, sleep laboratory | Miller et al. (2022)Other maker funded |
| Garmin Forerunner 245 Music | 5.4 bpm (absolute bias)Mean absolute error | ECG | n = 53, Overnight, sleep laboratory | Miller et al. (2022)Other maker funded |
HRV (RMSSD)3 studies
| Device tested | Result | Reference | Sample | Study |
|---|---|---|---|---|
| Garmin Fenix 6 | 10.52%Mean absolute percentage error | ECG | n = 13, Home, during sleep, 536 nights | Dial et al. (2025)Independent |
| Garmin Fenix 6 | 0.87Lin's concordance correlation | ECG | n = 13, Home, during sleep, 536 nights | Dial et al. (2025)Independent |
| Garmin Forerunner 245 Music | ICC 0.24Intraclass correlation | ECG | n = 53, Overnight, sleep laboratory | Miller et al. (2022)Other maker funded |
| Garmin Forerunner 245 Music | 33.1 ms (absolute bias)Mean absolute error (absolute bias) | ECG | n = 53, Overnight, sleep laboratory | Miller et al. (2022)Other maker funded |
More results (1)
| Device tested | Result | Reference | Sample | Study |
|---|---|---|---|---|
| Garmin Vivoactive 4 | ρc = 0.66 (moderate)Lin's concordance correlation | ECG | n = 263, 30-min standardised recording | Theurl et al. (2023)Independent |
Sleep stages (4-stage)3 studies
| Device tested | Result | Reference | Sample | Study |
|---|---|---|---|---|
| Samsung Galaxy Watch5 | κ = 0.42Cohen's kappa | Polysomnography (PSG) | n = 22, Two Korean sleep centres, in-lab PSG | Lee et al. (2023)Independent |
| Samsung Galaxy Watch5 | 64.9%Epoch-by-epoch agreement | Polysomnography (PSG) | n = 22, Two Korean sleep centres, in-lab PSG | Lee et al. (2023)Independent |
| Garmin Forerunner 245 Music | 50%Epoch-by-epoch agreement | Polysomnography (PSG) | n = 53, Sleep laboratory, 1 night, 9 h in bed, all devices worn together | Miller et al. (2022)Other maker funded |
| Garmin Forerunner 245 Music | κ = 0.25Cohen's kappa | Polysomnography (PSG) | n = 53, Sleep laboratory, 1 night, 9 h in bed, all devices worn together | Miller et al. (2022)Other maker funded |
More results (1)
| Device tested | Result | Reference | Sample | Study |
|---|---|---|---|---|
| Garmin Vivosmart 4 | κ = 0.21Cohen's kappa | Polysomnography (PSG) | n = 25, Sleep laboratory, 1 night | Schyvens et al. (2025)Funding not reported |
Sleep vs wake (2-stage)3 studies
| Device tested | Result | Reference | Sample | Study |
|---|---|---|---|---|
| Garmin Vivosmart 4 | > 90% (all devices)Sensitivity | Polysomnography (PSG) | n = 62, Sleep laboratory, 1 night | Schyvens et al. (2025)Funding not reported |
| Garmin Fenix 5S | Worse than actigraphyStudy finding (no single number) | Polysomnography (PSG) | n = 34, Sleep laboratory, 3 nights incl. disrupted night | Chinoy et al. (2021)Funding not reported |
| Garmin Vivosmart 3 | Worse than actigraphyStudy finding (no single number) | Polysomnography (PSG) | n = 34, Sleep laboratory, 3 nights incl. disrupted night | Chinoy et al. (2021)Funding not reported |
| Garmin Forerunner 245 Music | 89%Epoch-by-epoch agreement | Polysomnography (PSG) | n = 53, Sleep laboratory, 1 night, 9 h in bed, all devices worn together | Miller et al. (2022)Other maker funded |
More results (1)
| Device tested | Result | Reference | Sample | Study |
|---|---|---|---|---|
| Garmin Forerunner 245 Music | κ = 0.35Cohen's kappa | Polysomnography (PSG) | n = 53, Sleep laboratory, 1 night, 9 h in bed, all devices worn together | Miller et al. (2022)Other maker funded |
Total sleep time2 studies
| Device tested | Result | Reference | Sample | Study |
|---|---|---|---|---|
| Samsung Gear Sport | r = 0.59Pearson correlation | Research actigraphy | n = 45, Home, 7 days | Asgari Mehrabadi et al. (2020)Independent |
| Garmin Forerunner 945 | MAE 84.63 min (overestimate)Mean absolute error | Polysomnography (PSG) | n = 49, 1 night PSG + MSLT | Budig et al. (2022)Independent |
Blood oxygen (SpO2)8 studies
| Device tested | Result | Reference | Sample | Study |
|---|---|---|---|---|
| Samsung Galaxy Watch5 | Met ISO RMS ≤ 4% at normoxia and SpO2 < 90%Study finding (no single number) | Medical-grade pulse oximeter | n = 18, Induced hypoxemia (FiO2 14%, 12%, 10%), ISO 80601-2-61 | Walzel et al. (2023)Independent |
| Samsung Galaxy Watch4 | RMSD 1.8%Root-mean-square error | Arterial blood gas (SaO2) | n = 24, Hypoxia lab, SaO2 plateaus 70–100%, FDA/ | Browne et al. (2025)Independent |
| Samsung Galaxy Watch4 | RMSE 2.54 points (overnight, vs PSG oximetry)Root-mean-square error | PSG pulse oximetry | n = 51, In-lab overnight PSG, continuous SpO2 | Browne et al. (2024)Maker funded |
| Garmin Vivosmart 4 | 3.3% (rest)Root-mean-square error | Medical-grade pulse oximeter | n = 36, Rest, COPD outpatients | Støve et al. (2023)Funding not reported |
More results (2)
| Device tested | Result | Reference | Sample | Study |
|---|---|---|---|---|
| Garmin Venu 2S | 5.8% (RMSE 6.7%)Mean absolute error | Medical-grade pulse oximeter | n = 49, Spot readings, with and without chronic pulmonary disease | Jiang et al. (2023)Independent |
| Garmin Venu 2S | 6.7%Root-mean-square error | Medical-grade pulse oximeter | n = 49, Spot readings, with and without chronic pulmonary disease | Jiang et al. (2023)Independent |
3 more results in the database. SpO2 accuracy across devices →
Atrial fibrillation detection1 study
| Device tested | Result | Reference | Sample | Study |
|---|---|---|---|---|
| Samsung Galaxy Watch3smartwatch ECG app, inconclusive tracings counted | 85% (spec 75%)Sensitivity | 12-lead ECG | n = 201, Tertiary cardiology service, single-lead ECG algorithms | Mannhart et al. (2023)Funding not reported |
| Samsung Galaxy Watch3smartwatch ECG app, inconclusive tracings counted | 75%Specificity | 12-lead ECG | n = 201, Tertiary cardiology service, single-lead ECG algorithms | Mannhart et al. (2023)Funding not reported |
VO2max estimate3 studies
| Device tested | Result | Reference | Sample | Study |
|---|---|---|---|---|
| Garmin Forerunner 245 | 7.9% / 7.2% (two runs)Mean absolute percentage error | Indirect calorimetry | n = 35, Treadmill ramp test | Engel et al. (2026)Funding not reported |
| Garmin Fenix 6 | 7.05% (CCC 0.73)Mean absolute percentage error | Indirect calorimetry | n = 19, Graded exercise test and outdoor run | Carrier et al. (2025)Independent |
| Garmin Forerunner 920XT | 7.3%Mean absolute percentage error | Indirect calorimetry | n = 24, Lab | Passler et al. (2019)Independent |
Energy expenditure (calories)4 studies
| Device tested | Result | Reference | Sample | Study |
|---|---|---|---|---|
| Samsung Galaxy Watch5physical activity energy expenditure, 10 min | +56.76 kcalMean bias (signed) | Indirect calorimetry | n = 50, 10-min recumbent cycling intervals | Kostrna et al. (2026)Independent |
| Samsung Galaxy Watch6 / Watch7 | 10.10–12.55%Mean absolute percentage error | Indirect calorimetry | n = 148, 27-min intermittent treadmill running | Ferreira et al. (2026)Funding not reported |
| Garmin Fenix 5 | 15.9%–34.5% (range by intensity)Coefficient of variation | Indirect calorimetry | n = 25, Sitting, walking, running, sprints | Düking et al. (2020)Independent |
| Garmin Forerunner 955physical activity energy expenditure, 10 min | +68.61 kcalMean bias (signed) | Indirect calorimetry | n = 51, 10-min recumbent cycling intervals | Kostrna et al. (2026)Independent |
More results (1)
| Device tested | Result | Reference | Sample | Study |
|---|---|---|---|---|
| Garmin Fenix 6walking | 32.0% walk / 21.8% runMean absolute percentage error | Indirect calorimetry | n = 20, Outdoor 2-km walk (6 km/ | Le et al. (2022)Independent |
Respiratory rate1 study
Only maker-funded evidence for Samsung on this metric.
| Device tested | Result | Reference | Sample | Study |
|---|---|---|---|---|
| Samsung Galaxy Watch | RMSE 1.13 breaths/min (overnight average)Root-mean-square error | Polysomnography (PSG) | n = 195, Overnight PSG, nasal thermocouple reference | Jung et al. (2023)Maker funded |
Blood pressure3 studies
| Device tested | Result | Reference | Sample | Study |
|---|---|---|---|---|
| Samsung Galaxy Watch5 | SBP −0.34 / DBP +0.62 mmHgMean bias (signed) | Validated cuff (Omron M4) | n = 37, 28 days after one calibration | Walzel et al. (2026)Funding not reported |
| Samsung Galaxy Watch Active2 | 83% (spec 41%) for hypertensionSensitivity | 24-h ambulatory BP monitor | n = 40, 24-h ambulatory BP monitoring | Falter et al. (2022)Independent |
| Samsung Galaxy Watch (BP) | Pre/post calibration SBP error 6.8 ± 5.6 mmHgStudy finding (no single number) | Cuff used for calibration | n = 760, Real-world, 4 weeks post calibration | Han et al. (2023)Funding not reported |
Skin temperature1 study
Only maker-funded evidence for Samsung on this metric.
| Device tested | Result | Reference | Sample | Study |
|---|---|---|---|---|
| Samsung Galaxy Watch5 | r = 0.42 vs oral temperaturePearson correlation | Oral thermometer | n = 85, Nightly wrist skin temperature vs oral temperature on waking | Kim et al. (2026)Maker funded |
Verdict
Samsung adds blood pressure estimates on Android; Garmin offers much longer battery and works with iPhone too. Independent heart-rate evidence for both brands comes from older models.
Frequently asked questions
Which has better heart rate accuracy: Samsung Galaxy Watch or Garmin?
No study compares current models. Older-model results: Samsung Gear S2 had the highest error of seven devices (Shcherbina 2017); Garmin Forerunner 235 reached 0.81 concordance with ECG (Gillinov 2017).
Can Samsung Galaxy Watch blood pressure replace a cuff?
No. Samsung requires calibration with a cuff every 28 days and says the feature is not intended for diagnosis.
Device research records
Datasets, papers and validation results for the models named on this page.