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In this guide
The Withings Body Smart is a Wi-Fi and Bluetooth bathroom scale, model WBS13, that pairs four weight sensors reading to 0.1 lb with multifrequency bioelectrical impedance analysis. Eight users are recognized automatically at step-on; up to sixteen weigh-ins queue offline until the network returns. Four AAA batteries ship in the box, rated for an average fifteen months. Amazon held the offer at $129.95 on 2026-09-20 — In Stock, Amazon selling and shipping its own black unit.
Measured and estimated numbers leave this scale by different routes. Weight is read by the load cells — a zero reset at every step-on, a stance check that prompts you to center your feet — and BMI is computed from that reading and your profile height. Fat, muscle, water, bone, and visceral fat arrive instead from a low current crossing the lower body; Withings' explainer says the equations "estimate" fat-free mass and body fat is deducted from the total weight. Weight buyers get a solid instrument; body-composition buyers get a direction-over-time readout with conditions attached.
Our verdict
Buy the $129.95 Body Smart from Amazon for automatic weight tracking across up to eight users; treat its fat, muscle, water, and bone figures as trend estimates — Withings' documentation uses that word.
- A good fit for
- Households of up to eight that want weight logged automatically over Wi-Fi, weighed in repeatable morning conditions so the impedance estimates stay comparable day to day.
- We would skip it if
- Skip it while pregnant or carrying a pacemaker, ICD, or implanted electronic device unless the current is disabled; pass entirely without a smartphone or a reason to log weight.
Reasons to consider it
- The measured half is built like an instrument: four weight sensors reading to 0.1 lb, autoZero resetting the zero at every weigh-in, and Position Control prompting a centered stance for repeatable readings
- Eight users are recognized automatically at step-on, sixteen weigh-ins queue offline until sync returns, and the included AAA batteries carry a maker-estimated average life of fifteen months
- The mode list matches a real household: Baby Mode by weight subtraction — also the maker's recommended pet method — Pregnancy and Weight-Only modes that switch the impedance current off, and Eyes-Closed Mode that hides the numbers
The compromises
- Every composition figure is an equation output: the current runs up one leg and down the other, fat-free mass is estimated, and body fat is deducted from total weight — so hydration, time of day, and profile fields all move the numbers
- The readable-estimate protocol is demanding: bare feet, still stance, same time daily within 30 minutes of waking, nothing to eat or drink for two hours before, and an 18-plus profile; children and teenagers get no composition data at all
- App depth leans on the optional Withings+ subscription — $9.95 a month or $99.50 a year — for features like the daily weight trend, though the maker states it is not mandatory
What we have not verified: The Withings-sold offer at $119.95 seen in both selection-round reads was not reproducible on 2026-09-20 — Amazon's other-offers panel is script-loaded and returned nothing in the static page — so the article carries only the verified $129.95 reads from Amazon and withings.com. Search-level price history of roughly $70 promotions stayed unverified. No partner count for Health Mate sync appears on any current Withings page; the sync claim has only those named apps behind it. The product page gives two OS minimums (iOS 14 and Android 10 under Requirements, iOS 16 and Android 9.0 in the compatibility line). No independent reference-method test of Body Smart's impedance accuracy was consulted; the measured-versus-estimated framing rests entirely on Withings' own documentation.
The things in this guide
A closer look at the products, who they may suit, and what to check before buying.
Body Smart Scale (Black)
$129.95 from Amazon on 2026-09-20 — In Stock, Amazon's own black-unit offer — buys four 0.1-lb weight sensors, automatic eight-user recognition, Wi-Fi and Bluetooth sync, and AAA batteries rated for fifteen months.
Before you buy: The fat, muscle, water, and bone figures are impedance estimates, a word Withings uses itself; pregnant users and pacemaker or ICD carriers must disable the current, and composition needs a smartphone and an 18-plus profile.
Price checked September 19, 2026. Retailer prices can change.What the scale measures and what it estimates
Precision branding wraps the weight side: Withings Precision Technology, four weight sensors, autoZero resetting the zero at every weigh-in, and Position Control, a stance detector that nudges you until weight distributes evenly. The spec sheet grades that reading at 0.1 lb, or 50 g. On the impedance side, the product page describes multifrequency BIA sending an undetectable current, and the support explainer finishes the sentence: by measuring how tissues resist that current, "the scale can estimate the body composition of the user." Even the visceral-fat marketing line begins with the word estimate.
The health-insights page lays out the pipeline without dressing it up. BIA is the measurement of tissue resistance to a low-voltage current; "complex equations then estimate the amount of fat-free mass within the body," and body fat is deducted from the measured total weight. Fat, bone, and muscle sum to that weight, with water overlapping them rather than adding on. Profile fields matter for the same reason — the equations take age, height, and sex as inputs before the current ever runs.
The conditions attached to readable estimates
Estimates carry a protocol, and the support article lists it. Weigh at the same time daily, ideally within 30 minutes of waking, on bare feet, holding still; skip food and drink for two hours beforehand. Hydration shifts results because muscle carries the water that conducts; posture and muscle tension alone can move readings by up to 2 percent, and the same page resolves the wobble into its advice: "your monthly trend will accurately reflect the evolution of your body composition." Any single morning's fat figure does not.
Hardware conditions sit alongside the behavioral ones: a dirty glass surface degrades or defeats the measurement, and underfloor heating or nearby appliances can interfere. Athlete Mode exists because the default equations assume an ordinary body type, and the accuracy article tells muscular users to toggle it accordingly. The health-insights page goes further on limits — equations built on reference populations read worse in massive obesity, metal implants depress the fat figure, and the method's standardization, in that page's summary, still has open questions. Consistency is what makes the numbers usable.
Baby, pet, pregnancy, and eyes-closed modes
The household features read more kitchen than laboratory. Automatic recognition assigns each step-on to one of eight profiles without pressing anything, and sixteen weigh-ins queue offline until Wi-Fi or Bluetooth returns. Baby Mode works by subtraction — hold the child, and the scale deducts your weight — and the same mode is the maker's recommended answer for weighing pets. Eyes-Closed Mode hides the numbers entirely, showing motivational messages instead, for households where the figure does more harm than good.
Pregnancy Mode and Weight-Only Mode switch the impedance current off, leaving a plain weight scale for expecting users or anyone wanting one. Setup requires the Health Mate app on a smartphone; the support documentation states the scale cannot be set up from a computer. The measured half keeps working through all of it.
The $129.95 rung on a five-step ladder
The ladder above it is steep: $129.95 for the Body Smart, $229.95 Body Comp, $279.95 BodyFit, $499.95 Body Scan, $599.95 Body Scan 2, all listed on the Withings scales catalog on 2026-09-20. The discontinued Body+ holds no place in the line — its former address lands on that catalog. Amazon's offer, $129.95 as a first-party black unit anchored here, matched the direct-store price on the same day.
Health Mate is the required door, and it is free: weights and metrics sync to Apple Health, Apple Watch, Health Connect, and other fitness apps per the product page, which prints no partner count. Withings+ stacks on top at $9.95 a month or $99.50 a year after a free month, and Withings states it is not mandatory to use the scale — though extras like the daily weight trend sit behind it. Twelve monthly payments run $119.40 against the $99.50 annual plan.
Who should skip it
The contraindications write the first skip lines. Pregnant users are told to disable the impedance measurement — the scale "has not been tested and/or validated for usage during pregnancy" — and pacemaker, ICD, or implanted-electronic-device carriers are told they "should not use this device or should disable this feature in the app." Children and teenagers get no composition numbers at all; the feature is 18-plus, though a child's weight still reads through Baby Mode arithmetic.
Past the medical lines: anyone over 440 pounds is off the spec sheet, and anyone without a smartphone cannot set the scale up. A household that only wants weight on a screen is paying for an estimating engine nobody will switch on. A buyer chasing one trustworthy body-fat number is asking for something the standardization gaps in Withings' documentation do not promise — direction over time is what this instrument reliably delivers.
How we put this together
Built from the product pages and listings below, without test scores or results we have not measured. Specifications and prices change, so check the original page for the exact model, current price, delivery, and returns.
- Withings: Body Smart product page (opens in a new tab)
- Withings Support: Body Smart - Body Composition Accuracy Issues (opens in a new tab)
- Withings Support: Body Smart - Learn more about body composition and bioelectrical impedance analysis (BIA) (opens in a new tab)
- Amazon: Withings Body Smart listing (ASIN B0C3JNJPZ7) (opens in a new tab)
- Withings: Bioelectrical Impedance Analysis health insights page (opens in a new tab)
- Withings: smart scales catalog page (opens in a new tab)
