Garmin Index S2 integrates seamlessly with your Garmin Connect ecosystem. It pulls data into your health snapshot, links it to your metrics (Body Battery, HRV, VO₂ max estimates), and overlays it with sleep, respiration, and stress. That level of aggregation is unmatched by cheaper models. If you’re already embedded in Garmin’s ecosystem, this is the primary argument for S2. However, the device has limitations and is not the most precise scale on the market.
RENPHO, on the other hand, offers a dramatically lower price point ($21.99 at the time of your screenshot), a slick mobile app, Bluetooth syncing, and body composition metrics that look very similar on the surface. It lacks integration into Garmin Connect and doesn’t export directly to Google Fit or Apple Health in the same seamless fashion, but you can work around that with middleware apps (e.g. Health Sync or SmartScale Sync). It’s wildly popular because of how much it offers for so little, but its measurements—particularly for body fat and muscle mass—rely on single-frequency BIA (bioelectrical impedance analysis), which is known to be inconsistent unless conditions are controlled tightly (same hydration level, time of day, room temp, etc.).
Garmin Index S2 also uses BIA, but with multi-frequency support, giving it more reliable readings over time if used consistently. Still, even Garmin doesn’t market this as medically accurate—it’s about trend tracking, not point-in-time precision.
If your primary concern is tracking absolute numerical accuracy, none of these scales will deliver. They are consumer-grade, not DEXA-replacement tools. However, if your priority is data integration, trend fidelity, and minimal hassle, here’s a breakdown:
Garmin Index S2 – $129.99
Pros:
- Syncs automatically with Garmin Connect via Wi-Fi (no phone required after initial setup)
- Aggregates with stress, HRV, SpO₂, sleep, and exercise load metrics
- Supports multiple users with individual auto-recognition
- Tracks: weight, BMI, body fat %, skeletal muscle mass, bone mass, body water %, and trend graphs
- Data viewable in Garmin app, same interface you already use
Cons:
- Still uses BIA, so body fat and muscle estimates fluctuate with hydration
- Doesn’t integrate with non-Garmin apps like Fitbit or Apple Health without third-party tools
- 4.1 star average with notable complaints about Wi-Fi sync issues, especially for multi-user households
- Firmware updates often resolve issues but require using Garmin Express
- At over $100, you’re paying for ecosystem access, not better sensors
Who it’s best for:
- Anyone already using a Garmin watch and wants seamless data ingestion with no exports
- Users interested in long-term trend tracking more than isolated readings
- People who do not want to fuss with phone-based syncs or third-party apps
RENPHO Smart Scale – $21.99
Pros:
- Includes almost all the same metrics: weight, BMI, body fat %, muscle mass, bone mass, water %
- App (RENPHO Health or RENPHO Fit) is surprisingly slick and regularly updated
- Connects via Bluetooth quickly, usually with minimal issues
- Can sync to Apple Health, Samsung Health, Google Fit, MyFitnessPal
- Has been in production long enough to prove durable and maintain app support
Cons:
- No Wi-Fi—requires you to open the app and sync manually
- Doesn’t integrate with Garmin Connect without third-party middleware like FitnessSyncer or Google Fit bridges
- BIA is single-frequency, meaning wild variations are common, especially for water weight or lean mass
- App lacks advanced trend analytics or HRV overlay
- Data must be exported manually for use in spreadsheet analysis (CSV export via app is possible)
Who it’s best for:
- Budget-conscious users who are okay with handling their own data pipelines
- People not invested in Garmin’s ecosystem
- Users willing to manually sync and adjust conditions for consistent readings (always same time, same hydration)
Etekcity Smart Scale – $79.99
Pros:
- Similar to RENPHO but with slightly better construction and support
- Syncs with VeSync app, which connects to Alexa, Google Fit, Fitbit, and Apple Health
- 13 metrics, including metabolic age, protein %, visceral fat score
- App design is stronger than older versions of RENPHO
Cons:
- No direct Garmin support
- Bluetooth only (Wi-Fi option in higher-tier models)
- Slightly inflated cost for minimal improvements over RENPHO
Who it’s best for:
- Users wanting a compromise between RENPHO and Garmin
- More casual users looking for “fun” data, not deep health optimization
- Those who use multiple services (Fitbit, Alexa, etc.)
Key Differences
1. Integration with Garmin
- RENPHO and Etekcity will not automatically sync with Garmin Connect.
- To bridge them, you’d have to sync to Google Fit or Apple Health, then use FitnessSyncer, RunGap, or tapiriik to send data to Garmin. These services are often buggy, partial, or drop metrics in translation.
- Garmin Index S2 is natively built into Garmin’s data model and shows up instantly in Garmin Connect > Health Stats > Weight.
2. Trend tracking over time
- Garmin’s trend display for weight/body fat overlays well with Body Battery, HRV, sleep, and allows correlations.
- If you’re tracking complex multivariate shifts—weight dropping while HRV spikes, or muscle mass rising as SpO₂ stabilizes—this cross-referencing is essential.
- RENPHO lets you export CSVs, so you could manually build out data overlays in Google Sheets, but this is labor-intensive.
3. Measurement accuracy
- None of these are DEXA-grade. Expect up to 3–5% variation in body fat depending on hydration, meal timing, and even showering (wet feet can improve contact).
- Index S2 seems to reduce erratic swings over time, provided usage conditions are identical. Users report more day-to-day consistency.
- RENPHO shows more “jumpiness,” where body fat can swing 2–3% in 24 hours based solely on sodium intake or ambient temperature.
Final Decision Matrix
| Feature | Garmin Index S2 | RENPHO Smart Scale | Etekcity Smart Scale |
|---|---|---|---|
| Garmin Connect Sync | ✅ Native | ❌ Manual/indirect | ❌ Manual/indirect |
| Wi-Fi Sync | ✅ Yes | ❌ No | ❌ (Bluetooth only) |
| Multi-user Recognition | ✅ Automatic | ✅ Manual switching | ✅ Manual switching |
| Body Fat Consistency | ⚠️ Moderate (BIA-based) | ⚠️ Low (BIA-based) | ⚠️ Low (BIA-based) |
| Google Fit/Apple Health | ❌ (No native) | ✅ Yes | ✅ Yes |
| CSV Export | ❌ | ✅ Yes | ✅ Yes |
| App Quality | ✅ Stable | ⚠️ Functional | ⚠️ Moderate |
| Price | 💰 $129.99 | 🪙 $21.99 | 💸 $79.99 |
If you want a no-hassle pipeline where data moves from scale to Garmin to analysis without breaks, and you’re optimizing overlap across stress, HRV, weight, hydration, then the Garmin Index S2 is your best option despite the cost. You’re paying for ecosystem integrity, not absolute precision.
If your goal is purely to monitor weight, body fat, and muscle changes at a low cost, and you’re okay building your own analytics system via Sheets or Health Sync, RENPHO is hard to beat.
If you want both—precise trends and the ability to match them against respiratory rate, SpO₂, HRV, training load, REM distribution, or hydration—go Garmin. That’s the only scale that gives you true vertical integration across all those dimensions.
Further Smart Scales Comparison
| Feature | Garmin Index S2 | Withings Body+ | Eufy Smart Scale P2 Pro | RENPHO Smart Scale | Wyze Scale X |
|---|---|---|---|---|---|
| Price | ~$130 | ~$100 | ~$80 | ~$25 | ~$40 |
| Connectivity | Wi-Fi, Bluetooth | Wi-Fi, Bluetooth | Wi-Fi, Bluetooth | Bluetooth | Bluetooth |
| App Integration | Garmin Connect | Withings Health Mate | EufyLife | RENPHO Health | Wyze App |
| Third-Party Sync | Limited | Apple Health, Google Fit | Apple Health, Google Fit | Apple Health, Google Fit | Apple Health, Google Fit |
| Metrics Tracked | Weight, BMI, Body Fat %, Muscle Mass, Bone Mass, Body Water % | Weight, BMI, Body Fat %, Muscle Mass, Bone Mass, Body Water % | Weight, BMI, Body Fat %, Muscle Mass, Bone Mass, Body Water %, Heart Rate | Weight, BMI, Body Fat %, Muscle Mass, Bone Mass, Body Water % | Weight, BMI, Body Fat %, Muscle Mass, Bone Mass, Body Water % |
| User Profiles | Up to 16 | Up to 8 | Unlimited | Unlimited | Up to 8 |
| Display | Color LCD | Monochrome LCD | LED | LED | LED |
| Power Source | 4 AAA Batteries | 4 AAA Batteries | 3 AAA Batteries | 3 AAA Batteries | 4 AAA Batteries |
| Special Features | Seamless Garmin integration | Pregnancy mode, Baby mode | Heart rate monitoring, 3D virtual body model | USB rechargeable options | Pet, Baby, Luggage modes |
| Accuracy | High | High | Moderate | Moderate | Moderate |
| Best For | Garmin ecosystem users | Comprehensive health tracking | Budget-conscious users seeking extra features | Basic tracking needs | Families needing multiple modes |
Garmin Index S2
Ideal for users deeply integrated into the Garmin ecosystem. It offers seamless syncing with Garmin Connect, providing comprehensive data visualization when combined with other Garmin devices. However, it lacks extensive third-party app support. (Gizmochina)
Withings Body+
A versatile scale with robust app integration, supporting Apple Health and Google Fit. It offers multiple user profiles and modes, making it suitable for families. The Health Mate app provides detailed insights into body composition metrics. (Tom’s Guide)
Eufy Smart Scale P2 Pro
Offers a balance between price and features, including heart rate monitoring and a 3D virtual body model. It supports unlimited user profiles and integrates with major health apps, though some users report moderate accuracy levels. (BigaMart, Tom’s Guide)
RENPHO Smart Scale
A budget-friendly option that covers essential metrics. While it lacks Wi-Fi connectivity, it syncs via Bluetooth and integrates with popular health apps. It’s suitable for users seeking basic tracking without advanced features. (Coach)
Wyze Scale X
An affordable scale offering unique modes for pets, babies, and luggage. It supports multiple user profiles and integrates with major health apps. However, it lacks Wi-Fi connectivity, relying solely on Bluetooth. (Coach)
Recommendations
- Best for Garmin Users: Garmin Index S2 – Seamless integration with Garmin devices and apps.
- Best All-Rounder: Withings Body+ – Comprehensive features with broad app compatibility. (Reddit)
- Best Budget Option: RENPHO Smart Scale – Essential features at an affordable price.
- Best for Families: Wyze Scale X – Multiple modes catering to various household needs. (Coach)
- Best Feature-Rich Budget Scale: Eufy Smart Scale P2 Pro – Advanced features without a premium price tag.
When choosing a smart scale, consider your existing ecosystem (e.g., Garmin, Apple Health), desired features, and budget. Ensure the scale you select aligns with your health tracking goals and integrates smoothly with your preferred apps.