How to measure BMI on Xiaomi scales: full instruction with step-by-step photos

Xiaomi’s smart scales have long since ceased to be just a weighing device, becoming a full-fledged health assistant, and one of the key features of such devices is the calculation of body mass index (BMI), which helps to assess the weight’s fitness to height and identify the risks of obesity or dystrophy. However, many users face difficulties: the scales do not show BMI, the data in the Mi Fit application are not updated, the results seem inaccurate.

In this article, we will learn how to measure Xiaomi’s BMI (including the Mi Body Composition Scale 2, Xiaomi Smart Scale 2, and Mi Scale models), what settings to check in the app, and what to do if the numbers seem incorrect, and how to interpret the results and why they may differ from the calculations according to the classic formula.

What scales Xiaomi supports BMI measurement?

Not all Xiaomi smart scales can calculate BMI automatically, a feature only available in body composition models, and the main devices that support BMI measurement are:

• 🔹 Xiaomi Mi Body Composition Scale 2 is the most popular model with 13 parameters of analysis, including BMI, muscle mass and water level.
• 🔹 Xiaomi Smart Scale 2 - budget option with basic metrics (weight, BMI, fat mass).
• 🔹 Xiaomi Mi Scale (first version) – measures BMI, but without detailed analysis of body composition.
• 🔹 Xiaomi Mi Body Fat Scale – a specialized model for controlling fat mass, BMI is calculated automatically.

If you have a Xiaomi scale without a body analysis function (for example, a simple model Mi Scale Lite), then you will have to calculate your BMI manually using the formula or through third-party applications. You can check the support for the feature in the characteristics of the device on the official website or in the instructions.

Preparing for BMI measurement: 5 mandatory steps

To be accurate, it's important to prepare for the weighting, and even small details, such as the time of day or the moisture of the skin, can affect your performance.

Pay special attention to synchronization with the Mi Fit application. Without the correct profile setting (height, age, gender), the scales will not be able to calculate BMI. If you do not specify this data, the device will only show weight, and the body mass index will remain unavailable.

⚠️ Warning: If you have recently taken a bath, exercised, or drank a lot of water, your body composition (including BMI) may be overestimated due to altered body fluid levels.

Step-by-step: how to measure BMI on Xiaomi scales

Xiaomi's BMI measurement process is slightly different from conventional weighting, and here's a detailed guide for body composition analysis models:

1. Install the Mi Fit app (or Zepp Life for new models) and log in.
2. Enter the profile exact data: height, age, gender (this is critical for calculating BMI!).

On some models (e.g. Mi Body Composition Scale 2), BMI is displayed directly on the scale screen after weighing.

• 🔋 Battery level (at a discharge below 10%, the analysis function is turned off).
• 📱 Application Connection Status (Scales must be paired over Bluetooth).
• 📏 Correctness of the specified growth in the profile (if the growth is incorrect, BMI will be calculated incorrectly).

💡

If the scale shows an error of "E" or "Lo", it means overload or battery discharge. Replace the batteries (usually 4 AAA batteries) and repeat the measurement.

Why does Xiaomi’s scale show an incorrect BMI?

Differences between the BMI calculated by Xiaomi weights and the classical formula (weight in kg / (growth in m)²), — It's a common problem. Here are the main reasons:

A critical feature of Xiaomi scales is that they use bioimpedance analysis, which is sensitive to hydration levels. If you drank a lot of water before measuring, your BMI may be understated because of altered tissue resistance.

⚠️ Note: If your BMI by weight Xiaomi differs from the calculation by more than 10%, check the calibration of the device. To do this, stand on the scale with a known load (for example, a weight of 20 kg) and compare the readings.

How to interpret the results of BMI from Xiaomi scales?

Once you get the BMI value, it's important to decipher it correctly, and the World Health Organization (WHO) proposes the following classification for adults:

• 🟢 EMIT < 18.5 - Deficiency of body weight.
• 🟡 18.5–24.9 – Normal weight.
• 🟠 25–29.9 – Excess body weight (pre-obesity).
• 🔴 30–34.9: Obesity I degree.
• 🔴 35-39.9 Obesity II degree.
• 🟣 EMIT ≥ 40 - obesity III degree (morbidity).

However, this classification has nuances:

• 💪 For athletes with high muscle mass, BMI may be overestimated (muscles heavier than fat).
• 👵 For the elderly (65)+) normal BMI shifts to 22–28.
• 👶 Separate percentile tables are used for children and adolescents.

Xiaomi scales typically show not only the BMI figure, but also its interpretation (e.g., “Norma” or “Overweight”). These estimates are based on WHO standards, but do not take into account individual characteristics. For more accurate analysis, use additional metrics from the application: fat percentage, muscle mass, water level.

Comparison of BMI with Xiaomi scales and classical calculation

Many users have noticed that the BMI calculated by Xiaomi's scales does not match the weight/(growth × height) result. Why is this happening?

The fact is that Xiaomi scales use bioimpedance analysis (BIA), which measures not only weight, but also the distribution of fat, muscle and water, which allows you to refine the calculation of BMI based on body composition.

• If you have a high percentage of muscle, the scales can adjust your BMI downward.
• If there is too much fluid (swelling), BMI may be overstated.

To check the accuracy, perform the test:

1. Calculate the BMI by formula manually.
2. Compare it to the data from the Mi Fit app.
3. If the difference is greater than 0.5 units, check the profile settings and the calibration of the scales.

💡

Xiaomi scales are more accurate than the classic formula, because they take into account body composition, but for people with non-standard build (bodybuilders, pregnant women), it is better to focus on the percentage of fat, not BMI.

Frequent Mistakes and How to Avoid Them

Even experienced users sometimes make mistakes when measuring BMI on Xiaomi scales, and here are the most common ones:

• 🚫 Weighing in clothing or shoes – adds extra pounds and distorts BMI.
• 🚫 Carpet Use – Soft surface interferes with accurate measurement of bioimpedance.
• 🚫 Ignoring calibration – the scales should be reset periodically (the instructions indicate how to do this for your model).
• 🚫 Untimely synchronization – if you do not open the Mi Fit after weighing, the data may not be saved.

Another common problem is that scales don't keep their measurement history.

• No Internet connection on the phone.
• Closed application Mi Fit during weighing.
• Bluetooth malfunction.

To avoid data loss, always wait for the audible signal to beep at the end of the measurement and check that a new record appears in the application.

FAQ: Answers to popular questions