Choosing smart scales for the home often turns into finding a needle in a haystack, especially when it comes to popular models from Xiaomi. On store shelves and marketplace pages, it is easy to get confused with similar names where the difference lies in just one letter or number. Many users mistakenly believe that they are buying identical devices, but the functional gap between them can be an unpleasant surprise after unpacking.
The main difference is the number of measurements you measure: some models only show weight, while others can analyze body composition in 13 points. Understanding these nuances will allow you to avoid overpaying for unnecessary functions or, conversely, get exactly the level of control over health that you planned. In this article, we will discuss in detail the technical characteristics, connectivity features and software for both devices.
Before we get into the detailed comparison, it's important to note that both models operate in the Mi Home ecosystem, but they use different data processing algorithms, which affects reading accuracy and compatibility with third-party health services. Let's see which of the smart scaled platforms is right for you.
Conceptual differences in device functionality
The main watershed between the Xiaomi Mi Smart Scale 2 (NUN4049GL model) and the Xiaomi Mi Body Composition Scale 2 (XMTZC05HM model) is the depth of biometric data analysis. The first model, often referred to simply as the "Smart Scale", is an advanced version of conventional flooring scales. It can accurately measure weight, calculate body mass index (BMI) and determine body fat percentage using a simplified algorithm based on weight and height.
In turn, Body Composition Scale 2 is a full-fledged bioimpedance analyzer, which sends a weak, completely safe electrical signal through the human body to measure tissue resistance, and gives us a much more detailed picture of what goes from visceral fat to bone protein levels, and the difference in approaches is fundamentally changing the user experience.
⚠️ Note: Do not confuse these models with the first version of the scale (Mi Body Fat Scale), which had a glossy surface and less accurate sensors. Both models in question (Smart Scale 2 and Body Composition Scale 2) have matte coating and improved electronics.
If your goal is simply to monitor weight dynamics and overall BMI, then the baseline version may be enough, but for athletes or people who are looking at muscle mass in detail, not having a full bioimpedance analysis in a younger model will be a critical limitation, depending on how deep you plan to dive into biometrics.
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To get the most accurate data on the composition of the body, weigh yourself at the same time of day, preferably in the morning on an empty stomach, after visiting the toilet and before drinking water.
Comparative Characteristics Table
To visualize the difference, it's convenient to use a pivot table, which will help you quickly navigate technical parameters without going into long descriptions, and note the number of metrics you measure, which is a key marker of difference.
| Characteristics | Smart Scale 2 (NUN4049GL) | Body Composition Scale 2 (XMTZC05HM) |
|---|---|---|
| Number of parameters | 10 (Weight, BMI, % fat, muscle mass, etc.) | 13 (Including protein, bone mass, visceral fat) |
| Fat measurement method | Estimated (based on weight) | Bioimpedance analysis (BIA) |
| Maximum weight | 150 kg | 150 kg |
| Minimum weight | 5 kg | 5 kg |
| Nutrition | 4 AAA batteries | 4 AAA batteries |
As you can see from the table, the external dimensions and weight limits of the devices are identical. Both devices can withstand loads of up to 150 kilograms and start working at a minimum weight of 5 kg, making them suitable even for weighing children or pets (in the appropriate mode).
The Body Composition Scale 2 uses BIA (Bioelectrical Impedance Analysis) technology, which requires the feet to contact metal electrodes located on the surface of the scales. The Smart Scale 2 model does not have such electrodes in the classical sense, and the calculations are made mathematically, which gives a less accurate result for people with non-standard physiques.
Design, materials and construction
Visually, both devices look almost identical, often misleading customers: The case is made of tempered glass with a matte texture that hides fingerprints better than the glossy counterparts of the first generation, a decision Xiaomi has received high marks for aesthetics and practicality in everyday life.
On the top of the Body Composition Scale 2, you can see hidden metal electrodes in the form of a letter "C" or stripes at the bottom of the platform, which are necessary for bioimpedance analysis. In Smart Scale 2, the glass surface is completely uniform, because it does not need to take electrical readings from the user's feet to work.
- 📏 The dimensions of both devices are 300x300 This is the standard for most floor scales.
- 💡 The LED display is hidden under a layer of glass and lights up only when weighed, creating the effect of soaring numbers.
- 🛡️ The lower part is equipped with four anti-slip linings, providing stability on a smooth floor.
The build quality of both devices is high. The glass is strong enough to withstand daily use, but like any glass surface, it is afraid of spotting with heavy sharp objects. It is important to set the scales on a hard, flat surface - a carpet or soft coating will distort the readings of any of the devices.
Can I wash the scales under water?
Software and ecosystem
Both scale models are synchronized with the smartphone via Bluetooth 5.0. To work, you need to install the Mi Fit application (or its new version of Zepp Life) or use the universal Mi Home application. The initial setup process takes no more than a couple of minutes and does not require special technical knowledge.
The app collects data, plots changes, and allows you to track progress. In the case of Body Composition Scale 2, the app interface is more detailed: you see individual tabs for muscle mass, subcutaneous fat and visceral fat. For Smart Scale 2, some of this data is either missing or is a calculated approximation.
One of the useful features is that it supports up to 16 user profiles, and it automatically recognizes the user based on weight and measurement history, and if there are people in the family who are of similar weight, the app can suggest that you choose the profile manually after weighing it, which is convenient for the whole family to keep statistics.
It’s worth noting that integration with Apple Health and Google Fit works well for both models, allowing data to be imported into third-party training apps. However, if you use specialized sports apps that require accurate muscle mass data, Body Composition Scale 2 will provide a more robust base for analysis.
Measurement accuracy and calibration
Accuracy is the parameter that users often care about the most, both using high-precision manganese steel pressure sensors that deliver an error of just 50 grams, which is a great indicator for household use.
However, as mentioned earlier, the accuracy of fat percentage in Smart Scale 2 can vary. Because it doesn't use direct tissue resistance measurement, the algorithm relies on average data. For a person with an athletic build, scales can show an inflated percentage of fat, since muscles weigh more fat at the same volume.
⚠️ Note: Bioimpedance analysis (used in the Body Composition Scale 2) is contraindicated and is not recommended for people with pacemakers or other implanted electronic devices.
The scales don't require complex procedures to calibrate, but just set them on a flat surface, press the on button (or just stand on them), wait for zeros to appear, and then start weighing. If you've moved the scales to another place, you'd better repeat the zero procedure.
☑️ Precise weighing rules
Energy consumption and autonomy
Both models are powered by four type batteries. AAA, And it's a power-efficient Bluetooth module, and it's a bundle. OLED-display, one set of elements of power is enough for a long time - usually from 6 before 12 months with regular use (2-3 day-to-day).
The scales automatically go to sleep a few seconds after the user has left the platform. The battery charge indicator is displayed in the application and on the scale display itself, warning you to change the batteries in advance. This eliminates the situation when the device suddenly stops working.
It is important to use high-quality alkaline batteries. Cheap salt analogs can discharge faster and, worse, have the risk of leaking the electrolyte, which is guaranteed to put the electronic filling of the scales out of order. Batteries are replaced by opening the compartment on the bottom panel.
Final verdict: what to choose?
To sum up, the choice between Xiaomi Mi Body Composition Scale 2 and Xiaomi Mi Smart Scale 2 depends solely on your data detail needs. If you just want to keep track of weight and overall tone, the younger model will save you budget. If you are serious about sports or health control, the difference in functionality justifies the overpayment.
The key difference is that the Body Composition Scale 2 has a full bioimpedance analysis that allows you to measure real, rather than estimated, fat and muscle mass, making it a leader for fitness enthusiasts.
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For most health-conscious users, the Body Composition Scale 2 is a better investment thanks to advanced analytics that doesn’t require a subscription fee.
Both devices are excellent examples of the smart home concept from Xiaomi, offering reliability and stylish design. Regardless of your choice, you get a high-quality product that will serve you for years, provided you follow the basic operating rules.