Smart scales have come a long way. Both Withings and Fitbit make scales that connect to your phone, track body composition, and sync with health apps — but they take meaningfully different approaches, and the right choice depends on which ecosystem matters more to you.
Here's a straightforward comparison based on what matters for someone serious about weight tracking and health data.
The Product Lineups
Withings
- Body (~$99) — weight + BMI only
- Body+ (~$99–129) — weight, BMI, body fat %, water %, muscle mass, bone mass
- Body Comp (~$199) — everything above + visceral fat index, vascular age, nerve health score
- Body Smart (~$99) — updated body+ with improved BIA
Fitbit
- Aria Air (~$49–69) — weight + BMI + Fitbit app sync
- Aria 2 (discontinued, still available) — weight + BMI + body fat %
The first thing to note: Fitbit's scale lineup is significantly thinner than Withings, and Fitbit has not updated its scale hardware since the Aria Air (2019). Withings actively develops its scale line and has the Body Comp as its flagship.
Weight Accuracy
Both brands measure weight accurately. The Withings scales have a stated accuracy of ±100g (about ±0.2 lbs). The Fitbit Aria Air is rated ±0.2 lbs. For daily weight tracking purposes, both are precise enough — the scale-to-scale variance is smaller than the measurement noise you'll see from daily fluctuations anyway.
One practical advantage for Withings: it displays your measurement on the scale itself with a clear LCD readout, without requiring your phone nearby. The Fitbit Aria Air can display weight directly on-scale as well.
Body Composition: The Bigger Difference
This is where the comparison becomes significant. The Fitbit Aria Air does not measure body composition at all — it only tracks weight and BMI. The older Aria 2 measured body fat percentage, but is discontinued.
Withings Body+ measures body fat %, fat mass, muscle mass, bone mass, and water percentage using bioelectrical impedance analysis (BIA). The Body Comp adds visceral fat index, vascular age, and standing heart rate.
Bottom line on BIA accuracy: No consumer BIA scale is DEXA-scan accurate. Both Withings and Fitbit have error margins of ±3–5% for body fat percentage. The value is in tracking the trend over time under consistent conditions — not in the absolute number. For trend tracking, Withings is clearly superior because Fitbit's current scale doesn't offer it.
Sound familiar?
See your real trend — automatically.
The Scale Truth connects your Withings scale, MyFitnessPal, Apple Health, Google Fit, and Fitbit into one dashboard that filters the noise and shows what's actually happening.
Join the Waitlist — Free →Free beta · No credit card · Early access
App Ecosystems
Withings Health Mate
The Health Mate app is clean and functional. It shows historical trends for all measured metrics, has a good long-term weight trend view, and includes some health-focused features like a cardiovascular health score. It syncs seamlessly with Apple Health, Google Fit, and MyFitnessPal.
The limitation: Health Mate only shows you Withings data. It doesn't pull in your nutrition from MyFitnessPal or your sleep from your Apple Watch. The data is siloed to what the scale measures.
Fitbit App
The Fitbit app is built around Fitbit devices — primarily the wearables, not the scale. If you already own a Fitbit tracker or smartwatch, the Aria Air scale integrates seamlessly and your weight data lives alongside your steps, sleep, and heart rate in one app. This is a genuine advantage for Fitbit ecosystem users.
If you don't own a Fitbit wearable, the Fitbit app becomes less compelling — you're paying for a premium app ecosystem to support a single device that measures weight and BMI only.
Third-Party Integrations
| Platform | Withings | Fitbit Aria |
|---|---|---|
| Apple Health | ✓ Full sync | ✓ Weight only |
| Google Fit | ✓ Full sync | Limited |
| MyFitnessPal | ✓ Direct integration | Via Google Fit/MFP |
| Google Health Connect | ✓ | Limited |
| Garmin | ✓ | ✗ |
Price and Value
The Fitbit Aria Air at ~$49 is the cheapest option. But it only measures weight and BMI — something a $15 scale does just as well. You're paying for the Fitbit app integration, which is only worthwhile if you own Fitbit wearables.
The Withings Body+ at ~$99–129 is the strongest value in the smart scale market. You get accurate body composition tracking, a robust app, best-in-class third-party integrations, and hardware that Withings has been iterating on for over a decade.
The Withings Body Comp at ~$199 is for users who want the additional cardiovascular health metrics. Visceral fat index is particularly useful for health monitoring (visceral fat is more predictive of metabolic disease than total body fat), and vascular age gives a directional sense of arterial health. If that data matters to you, the price is justified.
The Verdict
Choose Withings if:
- You want body composition data (fat %, muscle mass)
- You use Apple Health, Google Fit, or MyFitnessPal
- You don't own a Fitbit wearable
- You want the best long-term platform for smart scale hardware
Choose Fitbit Aria Air if:
- You already have a Fitbit tracker or smartwatch and want everything in the Fitbit app
- You only need weight and BMI tracking, not body composition
- Budget is the primary concern
For most people serious about weight loss tracking, Withings is the stronger choice. The body composition data — even with its measurement limitations — adds a layer of information that a weight-only scale simply can't provide. And Withings' integration with the broader health app ecosystem is significantly better.