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Yes—the Xiaomi Body Composition Scale S400 is a genuine international product. Xiaomi lists it on global and regional websites, but “global” does not mean universal availability or one worldwide price. Its headline feature is a 25-indicator body-composition report generated with dual-frequency bioelectrical impedance analysis (BIA). That sounds comprehensive, but most of those figures are estimates, scores, ratios, or recommendations—not 25 independently measured clinical values.
The S400 is best viewed as an inexpensive trend-tracking scale for Xiaomi Home users and multi-person households. It is not a medical device, does not work with Mi Fitness, and offers only limited Apple Health synchronization.
At a glance
| Feature | Xiaomi Body Composition Scale S400 |
|---|---|
| Model | MJTZC01YM |
| Reported indicators | 25 |
| Weight range | 0.1–150 kg |
| Minimum division | 0.1 kg |
| Connectivity | Bluetooth Low Energy 5.0 |
| App | Mi Home/Xiaomi Home; not Mi Fitness |
| Users | Up to 36 profiles |
| Power | Three AAA alkaline batteries |
| Phone support | Android 8.0 or later; iOS 12.0 or later |
| Health-device status | Not a medical device |
Official specifications list dimensions of 300 × 300 × 24.55 mm and a net weight of 1.45 kg. Xiaomi claims up to 180 days of battery life, but that figure comes from laboratory testing with three 45-second weigh-ins per day at 25°C, so real-world runtime will vary. See Xiaomi’s specifications.
Is the S400 really a global Xiaomi product?
The S400 first appeared in China as the Mijia S400. International launch reporting was published on March 27, 2024, and Xiaomi now maintains a global product page plus regional listings for the Xiaomi Body Composition Scale S400. That makes it more than a China-only import.
#1 Best Overall
- Comprehensive 25 Body Composition Analysis: The Xiaomi Body Composition Scale S400 provides a detailed analysis of 25 essential body metrics, including body fat percentage, muscle mass, body water, protein, and bone mineral content. Gain deep insights into your physical condition to effectively manage your health and fitness goals with professional-grade data
- High Precision with Dual-Frequency BIA Technology: Experience exceptional accuracy with advanced Dual-Frequency Bioelectrical Impedance Analysis (BIA) technology. Key metrics, such as body fat percentage, are measured with a high correlation coefficient (≥0.93) against the DEXA gold standard, ensuring the data you receive is reliable and trustworthy for informed decision-making
- Smart Health Hub for the Whole Family: This smart scale automatically recognizes and stores data for up to 36 different users, making it perfect for family use. Each member gets a personalized profile within the Mi Home app, allowing everyone to track their unique health trends without data mixing
- Clear LED Display & Seamless App Integration: The scale features a bright, hidden LED screen that shows key readings like weight and heart rate instantly. For a complete overview, with the Mi Home app to view detailed historical trends, receive health insights, and connect with other Xiaomi ecosystem devices
- Versatile Weighing Modes & Practical Design: Beyond standard weighing, this scale offers specialized modes for various needs, including a mode for measuring babies or pets. Its large, non-slip platform (300x300mm) ensures stability, and the sleek, tempered glass design fits seamlessly into any bathroom decor
Availability still depends on the country. Xiaomi’s global listing does not establish a universal retail price, guaranteed stock, or a confirmed US checkout listing. The 99-yuan China launch price reported in 2024—about US$14 at the time—should be treated as launch context, not as a current US or international price. Check the local Xiaomi store or an authorized retailer for live price, warranty, returns, and app-region compatibility.
Xiaomi global product page | 2024 launch and China-price context
What are the 25 health metrics?
Xiaomi describes the S400 as producing 25 indicators. Calling them all “measurements” is misleading because the report combines scale data, electrical-impedance estimates, calculated values, labels, and suggested targets.
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- Weight
- Heart rate
- BMI
- Body score
The scale can display weight, body-fat percentage, heart rate, battery status, Bluetooth status, units, and prompts directly. The full report is viewed in Xiaomi Home. Heart rate is static monitoring during a weighing session, not continuous monitoring or a clinical heart-rate test.
Composition estimates
- Body-water mass
- Body-water percentage
- Fat mass
- Body-fat percentage
- Protein mass
- Protein percentage
- Muscle mass
- Muscle percentage
- Bone-mineral content
- Bone-mineral percentage
- Visceral-fat rate
- Basal metabolic rate
- Lean body mass, described in one Xiaomi support page as “degreased weight”
- Body type
- Estimated waist-to-hip ratio
- Body age
- Skeletal-muscle mass
These figures are algorithmic estimates derived from impedance, weight, and profile information. “Visceral-fat rate” is not a direct scan of visceral fat, and bone-mineral content is not the same as a clinical bone-density test.
Targets and recommendations
- Weight control
- Muscle control
- Fat control
- Standard weight
These are advisory outputs: they suggest how weight, muscle, or fat might relate to the profile entered in the app. They should not be interpreted as medical treatment targets.
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Xiaomi’s official list of all 25 indicators
How dual-frequency BIA works
The S400 sends a small electrical signal through the body using two frequencies. Xiaomi says its 50 kHz low-frequency signal assesses extracellular fluid, while the 250 kHz high-frequency signal is used to assess intracellular fluid and cellular components.
Xiaomi also claims that selected body-fat data achieved a correlation coefficient of at least 0.93 against DEXA in a study report identified as BSU20220389. That is a company-reported correlation claim, not proof that the scale provides DEXA-level accuracy.
Correlation describes how readings move together; it does not say that every individual result is within a particular number of percentage points of DEXA. The cited claim also concerns selected fat-related data, not all 25 indicators. Hydration, food and alcohol intake, recent exercise, skin contact, foot placement, and time of day can all affect BIA results.
For that reason, use the S400 to follow consistent trends rather than diagnose a condition or make decisions from one reading. Xiaomi itself says the results are for reference only and that the scale is not a medical device.
App, phone, and connectivity requirements
The S400 uses Mi Home/Xiaomi Home. Xiaomi’s support documentation specifically says it is not compatible with Mi Fitness and does not pair directly with other apps.
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- Install and open Mi Home/Xiaomi Home.
- Step on the scale to wake it.
- Tap the + icon in the upper-right corner.
- Select Add a device.
- Choose Xiaomi Body Composition Scale S400.
- Select the device and tap Connect device.
- Create or select a user profile and enter the requested information.
- Measure barefoot with both feet fully contacting the electrode pads.
Xiaomi lists minimum app versions of iOS 8.7.204 and Android 8.7.703 in its support documentation, alongside Android 8.0+ and iOS 12.0+ phone requirements.
Rank #3
- Large Screen Display: 5.3" color screen to instantly display 8 key metrics: weight, BMI, body fat, muscle mass, water, visceral fat, bone mass, and body type. Our weight scale fits all foot positions securely, with the compact 11"x11" sturdy platform
- Precision Measurement & Safety Design: Our body weight scale provides 0.1 lb/0.05 kg increments and supports weights up to 400 lb/180 kg, designed to provide consistent weight readings when used on a hard, level surface. Complementing its technical performance, the 5mm tempered glass platform and anti-slip textured surface provide enhanced stability and safety for users of all ages and fitness levels, from adults to athletes
- 14 Key Body Metrics & Health Analysis: This GE body fat scale measures 14 essential health indicators including weight, body type, body fat, BMI, skeletal muscle, muscle mass, protein, BMR, fat-free body weight, subcutaneous fat, visceral fat, body water, bone mass and metabolic age. The data empowers you to create personalized fitness plans based on detailed body composition trends
- Track Progress & Reach Goals: Our Digital bathroom scales with free Fit Profile app monitor your weight, muscle mass, and body fat using easy-to-read charts and historical data over days, weeks, or years. Additionally, this weight scale for body has the goal-setting feature, allowing you to set and review progress targets
- Multi-User & Fitness App Integration: The bluetooth body scale accommodates unlimited users while maintaining individual profiles for personalized tracking. It seamlessly syncs with the free Fit Profile app, Apple Health, Samsung Health, Health Connect and Fitbit, allowing easy sharing of body composition trends with loved ones
Bluetooth versus gateway syncing
Basic weighing does not require a gateway. With ordinary Bluetooth, the phone should be nearby for convenient synchronization.
A separately purchased compatible Bluetooth gateway can upload measurements automatically when the phone is not directly connected and can support cloud access through Xiaomi Home. Therefore, a “Bluetooth gateway not connected” message does not necessarily indicate a faulty scale. If you do not need remote syncing, the warning can generally be ignored.
Is it suitable for a family?
The S400 can store up to 36 user profiles: one primary Xiaomi account, up to five shared Xiaomi accounts, and up to five virtual users under each account.
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It supports adult and child profiles, guest mode, baby-holder weighing, pet weighing, balance testing, and small-object weighing. Guest measurements are not stored. Objects under 10 kg are treated as small objects and ordinary readings are not saved; use baby-holder mode when weighing an infant and saving the result.
Automatic recognition can fail when two users’ weights differ by no more than approximately ±2 kg. Families with similar-sized users should expect to select the correct profile manually.
Age, height, and safety limits
Xiaomi says full body-composition measurement is intended for ages 6–80. Children under six and adults over 80 can use weight measurement only. The body-composition algorithm supports 20–150 kg and heights of 90–200 cm. Adolescents’ results are for reference because their bodies are changing rapidly.
Rank #4
- Large LCD Screen Display: Instead of normal LCD display scales, the Runstar scale features a large display screen that shows 6 key measurements, including weight, body fat rate, BMI, muscle mass, body water rate and bone mass. You can completely free your hands to read these measurements at a glance without having to open your APP for every measurements.
- Three Guarantees for High Accuracy: This ultra-precision body fat scale, adopting the advanced BIA technology, is equipped with 4 high sensitive electrodes and 4 high precision G-shape sensors that have passed 100,000 times sensor performance tests to enhance accuracy.The scale ensures accurate measurement results to within 0.2lb/100g and has a maximum weight capacity of 400lb/180kg.
- 13 Essential Body Composition data Analyzer: Runstar Scale utilizes electrical Bio-Impedance Measurement Technology to calculate including Weight, BMI, Body Fat, Fat-free Body Weight, Subcutaneous Fat, Visceral Fat, Water, Muscle Mass, Bone Mass, Protein, BMR and Body Age. You can monitor and track your body data over time periods (by weeks, months or even years) on Starfit App anytime anywhere, which can help guide you towards a healthier lifestyle or track your fitness progress.
- User-friendly APP: You can download the Starfit app from App Store or Google Play. The smart scale supports offline measurement, which allows the data be measured and automatically synced onto the APP after connecting the app to complete the first measurement. The app also syncs easily with other fitness apps like Apple Health, Health Connect, and Fitbit.
- Family Health Guardian: With the ability to create up to 24 user profiles and identify the user instantly when one steps on, the RunSTAR Scale is perfect for families and friends who want to track their body data for health. (Baby Mode supported.) The scale is great for bodybuilders, weight loss enthusiasts, and anyone who wants to maintain a healthy lifestyle.
Do not use the body-composition function with an electronic medical implant such as a pacemaker unless a physician confirms it is safe. Xiaomi also warns that estimates may be less reliable for pregnant people, athletes, older adults, and people with unusual body composition. Balance testing is not recommended for pregnant people, older adults, or anyone with poor balance. See Xiaomi’s supported-user guidance.
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What actually syncs to Apple Health?
On iPhone, Xiaomi documents synchronization for only four data types:
- Weight
- Body-fat rate
- Height
- Body-fat index
To enable it, open Settings → Health → Data Access & Devices → Mi Home/Xiaomi Home, then grant the relevant permissions. Xiaomi says only newly measured data sync after permissions are enabled, and only the primary account’s data is synchronized.
There is no documented promise that all 25 indicators export to Apple Health. The available documentation also does not establish full direct support for Google Fit, Fitbit, Samsung Health, or other third-party platforms. This is a significant limitation for buyers who want one central health-data history.
Xiaomi’s Apple Health instructions
How to get more consistent readings
- Weigh yourself at roughly the same time each day.
- Use the same hard, level floor.
- Measure barefoot with both feet fully on the electrode pads.
- Avoid comparing readings immediately after exercise, eating, drinking alcohol, or consuming a large amount of fluid.
- Look at multi-day or multi-week trends rather than a single body-fat percentage.
- Clean the scale and the soles of your feet if the body-composition result fails.
Xiaomi recommends cleaning the soles and scale surface with a moist towel. If necessary, measure while connected to the app using the online measurement flow. Regional Xiaomi product guidance
Troubleshooting common problems
The scale cannot be discovered
- Delete the scale from Xiaomi Home.
- Open the battery cover.
- Press the reset button with an ejection pin for seven seconds.
- Update or reinstall Xiaomi Home.
- Confirm the phone meets the Android or iOS requirements.
- Keep Bluetooth enabled and the phone close to the scale.
- Pair again through + → Add a device.
Family profiles are mixed up
When users are within roughly 2 kg of one another, automatic recognition may fail. Select the correct user manually in the app.
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The body-fat result is missing or inconsistent
Check barefoot contact, foot placement, surface cleanliness, and hydration-related variables. Do not treat a single unusual result as a diagnosis.
S400 versus the alternatives
| Scale | Best for | Main trade-off |
|---|---|---|
| Xiaomi S400 | Detailed low-cost trend tracking and large households | Mi Home only, estimated metrics, limited Apple Health export |
| Xiaomi Smart Scale S200 | Weight, BMI, basic recommendations, and Xiaomi Home | Fewer indicators; 0.5 kg minimum increment; no S400-style report |
| Mi Smart Scale 2 | Simple entry-level weight tracking | No 25-indicator analysis or static heart-rate monitoring |
| Withings Body Smart | Health-app ecosystem and long-term trend tracking | Different ecosystem and typically a higher-value software/support proposition rather than Xiaomi integration |
The S200 is smaller and lighter at 280 × 280 × 22 mm and 1.2 kg, but its minimum increment is 0.5 kg. Xiaomi’s comparison documentation confirms that the Mi Smart Scale 2 lacks the S400’s 25-indicator report and static heart-rate feature. Withings advertises up to eight recognized users, trend tracking, and unlimited storage in its app. The meaningful comparison is not simply the number of metrics; it is the app, data portability, support, warranty, and price in your market.
Xiaomi Smart Scale S200 | Xiaomi comparison information | Withings smart scales
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Who should buy the Xiaomi S400?
The S400 makes sense for a budget-conscious buyer who wants weight and body-composition trends, already uses Xiaomi Home, or needs one scale for a large household. Baby, pet, guest, and small-object modes add practical flexibility.
It is a poor fit if you need clinical body-composition measurement, Mi Fitness compatibility, complete Apple Health export, extensive third-party integrations, hand electrodes, or segmental body analysis. It is also a risky purchase through a grey-market importer unless local warranty, returns, replacement support, and app-region behavior are clear.
Before buying, check five things: local stock, current regional price, authorized warranty, return policy, and whether the Xiaomi Home region selected in the app supports the product.
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