What Smart Scales Actually Measure
The electrodes in smart scales send a harmless electrical current through your body. By measuring resistance (bioelectrical impedance analysis, or BIA), they estimate body fat %, muscle mass, bone density, water weight, BMI, and basal metabolic rate.
Important caveat: Consumer-grade BIA scales are accurate to within ±3–5% for body fat. They're great for tracking trends over time, not for precise medical readings.
Top Picks
1. Withings Body Composition Smart Scale — Best Overall
Withings is the premium choice. Clinical-grade accuracy, seamless app integration with Apple Health and Google Fit, and a beautiful design that looks good in any bathroom.
- Measures: Weight, body fat %, muscle mass, water %, bone mass
- Max weight: 396 lbs
- App: Clean, intuitive, long-term data trends
🏆 Best Overall Smart Scale
The Withings Body Composition scale is the one we recommend for anyone serious about tracking their health metrics over time.
Check Price on Amazon →2. Renpho Smart Scale — Best Budget
Renpho sells millions of scales for under $20. The app is functional, data syncs to Apple Health and Samsung Health, and the accuracy is surprisingly good for the price.
- Measures: Weight, body fat %, muscle, bone, water
- Price: ~$18
💰 Best Budget Smart Scale
The Renpho Smart Scale delivers solid body composition tracking at a fraction of the premium price.
Check Price on Amazon →3. Fitbit Aria Air — Best for Fitbit Users
If you live in the Fitbit ecosystem, the Aria Air is the seamless choice. Syncs directly to your Fitbit dashboard.