TL;DR
- No consumer smart scale gets close enough to DEXA to trust its body-fat percentage as an absolute, and that includes Withings, Renpho, and Eufy. Validation studies put BIA versus DEXA error at several percentage points, with one finding a mean difference near 10%.[1][2]
- The brand matters less than the method. All three use bioelectrical impedance, which has the same hydration-driven error regardless of price; a $229.95 Withings is not 10x more accurate than a $25 Renpho.[4]
- What you actually buy with the pricier scales is more electrodes and metrics (Renpho's MorphoScan adds segmental BIA), not DEXA-grade accuracy.[5]
- Use any of them for weight and your own body-fat trend under fixed conditions; use DEXA when the true number matters. Note Eufy discontinued its US smart-scale line in March 2026.[6]
Buying a more expensive smart scale to get an accurate body-fat reading is the wrong fix, because the limitation is the measurement method, not the hardware tier. Withings, Renpho, and Eufy all estimate body fat with bioelectrical impedance (BIA), and the peer-reviewed evidence says BIA misses DEXA by several percentage points for an individual. This guide compares what each brand offers and what the independent science says BIA can and cannot do. Verified 2026-06-07.
How close does BIA get to DEXA? The studies
BIA sends a small current through the body and infers fat from resistance, which makes it sensitive to body water rather than fat alone. An observational validation of consumer smart scales found them accurate for weight but inaccurate for body composition.[1] In a cross-sectional study of youth with overweight or obesity, automated BIA differed from DEXA on body-fat percentage by a mean of about 10%, with the largest individual residuals near 24%.[2] In adults in a weight-loss program, BIA underestimated body fat relative to DEXA, with 95% limits of agreement reaching roughly 12.7%.[3] The pattern is consistent. BIA is fine for population averages and your own trend, but the error band for any single reading is too wide to call a true value.
Verified price and feature comparison
| Spec | Withings Body Comp | Renpho MorphoScan | Eufy Smart Scale P3 |
|---|---|---|---|
| Price | $229.95[4] | ~$150-$210[5] | ~$99.99 (line discontinued US)[6] |
| BIA type | Two-frequency[4] | 8-electrode dual-frequency, segmental[5] | Standard foot-to-foot BIA[6] |
| Segmental (limb-by-limb) | No (exclusive to Body Scan)[4] | Yes[5] | No[6] |
| Metrics tracked | Body fat, muscle, water, visceral fat, vascular age[4] | 50+ metrics[5] | 16 metrics[6] |
| Body-fat accuracy vs DEXA | BIA-class error of several points; not DEXA-grade for any of the three[1][2] | ||
What you actually pay more for
The Withings Body Comp ($229.95) uses a two-frequency BIA and reads body fat, muscle, water, visceral fat, and extras like vascular age. Its own page notes that segmental composition is reserved for the pricier Body Scan.[4] Renpho's MorphoScan ($150-$210) is the most capable of the three on paper, using an 8-electrode dual-frequency design with limb-by-limb segmental analysis and 50-plus metrics.[5] The Eufy P3 (around $99.99) covers the basics with 16 metrics from a standard foot-to-foot setup.[6] More electrodes and more frequencies give you a richer dashboard and arguably steadier readings, but none of that closes the gap to DEXA for absolute body-fat percentage; the published BIA-DEXA error applies across the category.
A note on availability
Eufy discontinued its Smart Scale line on eufy.com in the United States as of March 2026, though units remain on third-party retailers.[6] If you want a body-composition scale you can register and support directly through the maker, Withings and Renpho are the safer 2026 buys. We have not run our own DEXA comparison on these units; every accuracy figure here comes from independent peer-reviewed BIA-versus-DEXA studies.
How to use a body-fat scale honestly
- Trust the weight, and track its trend across weeks, not days.
- Standardize body-fat readings: same time of day, same hydration, before eating, so the trend is comparable to itself.
- Read your own body-fat trend, not the absolute number, since the offset versus DEXA tends to be consistent for one person even when the value is off.
- Use DEXA when you need a true body-fat figure for a meaningful decision.
The verdict: pick the Renpho MorphoScan if you want the most metrics and segmental BIA for the money, the Withings Body Comp if you want the cleaner ecosystem and extra cardiovascular readouts, and skip the Eufy P3 unless you find it cheap on a third-party seller, since its US line is discontinued. Just do not pick any of them expecting DEXA-grade body fat; the BIA error of several percentage points applies to all three. To work with body composition numbers, use the Body Fat Percentage Calculator, and for the gold-standard gap read DEXA vs Smart Scale Body Fat 2026 and Are Smart Scales Accurate 2026.
Verified 2026-06-07. Every accuracy figure is sourced to a named peer-reviewed validation study; prices and availability change without notice.
FAQ
Is the Withings, Renpho, or Eufy the most accurate for body fat?
For absolute body-fat percentage, none is accurate against DEXA; all three use BIA, which misses DEXA by several percentage points. The brand mainly changes how many metrics and electrodes you get, not DEXA-grade accuracy.[1][2]
How far off is a smart scale from a DEXA scan?
Studies put BIA-versus-DEXA error for an individual at several percentage points, with one youth study finding a mean difference near 10% and adult limits of agreement reaching about 12.7%.[2][3]
Does a more expensive scale read body fat more accurately?
Not against DEXA. A pricier scale like the Renpho MorphoScan adds segmental analysis and more metrics, and dual-frequency BIA can read more steadily, but the method's error band versus DEXA is similar across the category.[5][1]
Is the Eufy Smart Scale still available?
Eufy discontinued its Smart Scale line on eufy.com in the US as of March 2026, though stock remains on third-party retailers. For direct maker support in 2026, Withings or Renpho are safer choices.[6]
References
- 1 Accuracy of Smart Scales on Weight and Body Composition: Observational Study (accurate for weight, inaccurate for body composition) — JMIR mHealth and uHealth (PMC8122302) (2021)
- 2 Body fat assessment by automated BIA vs DEXA in youth with overweight/obesity (mean BIA-DEXA difference ~10%, max residual ~24%) — BMC / cross-sectional study (PMC9347159) (2022)
- 3 Percentage of Body Fat using BIA and DEXA in a weight-loss program (95% limits of agreement up to ~12.7%) — International Journal of Environmental Research and Public Health (PMC3613423) (2013)
- 4 Withings Body Comp product page ($229.95, two-frequency BIA; segmental analysis exclusive to Body Scan) — Withings (2026)
- 5 RENPHO MorphoScan body composition scale (8-electrode dual-frequency segmental BIA, 50+ metrics) — RENPHO (2026)
- 6 eufy Smart Scale P3 (16 metrics; eufy Smart Scale line discontinued on eufy.com US as of March 2026) — eufy (2026)