How to find out the real battery capacity on the Xiaomi smartphone: all working methods

You've noticed that Xiaomi's smartphone is running out too fast, even though it's supposed to last longer, and maybe the actual battery capacity is far from what the manufacturer said. Over time, lithium-ion batteries degrade, and after 300 to 500 charging cycles, their capacity can drop by 20 to 30 percent, but how do you check this yourself without going to a service center?

In this article, you will find 5 proven ways to determine the current battery capacity on Xiaomi, Redmi and POCO devices, from simple USSD codes to advanced methods through ADB and engineering menus. We will also explain why the readings in the system settings often do not match reality, and what to do if the battery capacity is critically low. All instructions are relevant for devices on MIUI 12-14 and HyperOS (including models from 2020-2026).

Why the actual battery capacity is different from the stated

Manufacturers have given a nominal battery capacity (e.g., 5,000 mAh), but that number has decreased over time.

• 🔋 Natural degradation: Lithium-ion batteries lose up to 1-2% of capacity per month when used actively. after 2 years of operation, the loss can reach 30%.
• 🔌 Improper charging: Constant use of "fast" charging (30W+), overheating during charging or discharge to 0% accelerate wear.
• 📱 Programmatic limitations: MIUI can artificially lower the maximum charge level (e.g. up to 80%) to extend battery life.
• 🏭 Marriage or Fake: On Budget Models (Redmi) 9A, POCO M3) batteries with a capacity below the declared already "out of the box».

It's important to understand that even if a smartphone is 100 percent charge, the actual capacity may be lower, for example, a 4,000 mAh battery after a year of use actually holds only 3,200 mAh, but the system displays "full charge" as 100 percent. To find out the truth, you need special tools.

Method 1: USSD code for quick check (not working on all models)

The easiest method is to use service code.It works for most Xiaomi devices on MIUI 12-14, but may not work on new models with HyperOS (for example, Xiaomi 14 or Redmi Note 13 Pro+).

Instructions:

1. Open the Phone app.
2. Enter the code: ##4636###.
3. In the menu that opens, select Battery Information.
4. Note the line Battery level and Capacity or Health.

What do the numbers mean?

⚠️ Note: If you enter the code and you see a message saying "No communication" or the menu doesn't open, your model doesn't support this method.

Method 2: Engineering menu (for advanced users)

The Engineering Mode gives you access to hidden system settings, including detailed battery information, which works on most Xiaomi devices, but requires caution – wrong actions can disrupt your smartphone.

Step-by-step:

1. Open the Phone app and type in ##36446337## (or #4636## → Engineer mode).
2. Go to Battery (also known as Battery Information or MBAT).
3. Find parameters: Battery capacity - current capacity in mAh. Battery health - percent of wear (for example, 92% means that the battery has lost 8% of capacity). Voltage - voltage (normal: 3.7-4.2 V when fully charged).

Example of data decryption:

Battery capacity: 4500 mAh (rated 5000 mAh → 10% wear)




Battery health: 90% (good condition)




Voltage: 4.18 V (normal for 90% charge)

⚠️ Note: Do not change any parameters in the engineering menu unless you are sure of their purpose. For example, resetting the battery calibration (Battery calibration) can lead to improper display of charge.

Find Battery | Compare Battery capacity to face value | Evaluate Battery health (should be >80%) | View voltage (3.7-4.2 V)

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Method 3: Applications for diagnostics (AccuBattery, CPU-Z)

If the service codes don't work, use third-party apps that analyze the data from the battery controller and show the actual capacity.

• 📊 AccuBattery (free version with limitations) - shows real capacity, discharge rate and number of charging cycles. Accuracy: ±5%.
• 🔍 CPU-Z (Battery section - displays current capacity, voltage and temperature.
• 🛠️ AIDA64 — Detailed information about the battery, including technology (Li-Po/Li-Ion) producer.

How to use AccuBattery:

1. Install the app from Google Play.
2. Charge your phone to 100% and connect to the app.
3. Go to Health, and it will show: Estimated capacity (e.g., 4300 mAh instead of 5,000 mAh), Percentage of wear (e.g., 14% means the battery has lost 14% capacity), Number of charge cycles (more than 500 critical wear).

Screenshot from AccuBattery (example for Redmi Note 10 Pro):

Design capacity: 4520 mAh (nominal 5020 mAh)




Depreciation: 10%




Charging cycles: 312

💡

For accurate analysis in AccuBattery, use your phone for 2-3 days – the application will collect enough data to calculate the real capacity.

Method 4: ADB-commands (maximum accuracy)

The method is for power users ready to connect a smartphone to a computer. ADB (Android Debug Bridge) allows you to get data directly from the battery controller, bypassing the limitations of MIUI.

What you need:

• 🖥️ Computer with Windows/macOS/Linux.
• 🔌 Cable USB Type-C (original, undamaged).
• 📦 Installed drivers ADB and Fastboot (download from Android site).

Instructions:

1. Turn on USB Debugging on your smartphone: Go to Settings → About Phone → MIUI Version. Tap 7 times on the MIUI Version to activate Developer Mode. Go back to Settings → Additional → Developer Tools and enable USB Debugging.

Connect the phone to your computer and confirm access.

cmd

adb shell


dumpsys battery

capacity: 85


charge_counter: 3800000

Here. charge_counter — real capacity in microamper-hours (3800000 μAh = 3800 mAhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh).

⚠️ Attention: If the value charge_counter overestimated (for example, 10000000 battery-power 5000 mAh), this may indicate a failure of the controller, in which case calibration or replacement of the battery is required.

Method 5: Disassembly of the phone and visual inspection

If the software methods don't give a clear answer, the last thing you can do is physical testing, and that's true for devices older than 3 years or after a drop or a drop.

How to check the battery after disassembly:

1. Turn off the phone and remove the back cover (for removable battery models, such as the Redmi 4X or Mi A1).
2. Check the battery for the subject: 🔥 Bloating (the cover does not fit tightly, the screen is raised»). 💧 Corrosion traces (green/white plaque on contacts). 📏 Markings – compare the nominal capacity (written on the battery) with the declared.

• Connect the probes to the + and - contacts.
• Normal voltage: 3.7-4.2 V at 100% charge.
• If the voltage is below 3.0V, the battery is worn out.

Examples of markings on Xiaomi batteries:

⚠️ Warning: Disassembling the phone voids the warranty.If you're unsure of your skills, contact the service center. Xiaomi batteries are often glued, and removing them without special tools can damage the plumes.

💡

If the battery is swelling, replace it immediately! The risk of fire or damage to the internal components of the phone is extremely high.

What to do if the battery capacity is critically low

If the test shows that the actual battery capacity is below 70% of the nominal value, it's time to take action.

• 🔄 Battery calibration (sometimes helps when the controller fails): Discharge the phone until it turns off automatically. Connect to the original RAM and charge to 100% without interruption. Repeat 2-3 times.

Battery replacement

• Xiaomi’s official service is a 6-month warranty, but the price is higher.
• Unofficial workshops are cheaper, but the risk of running into a poor-quality battery.

Cost of replacement (2026): 1500–4,000 ₽ model-wise.

Optimizing consumption

• Turn off Adaptive Brightness and set 60-70%.
• Turn off 5G and NFC if you are not using it.
• Limit the background activity of applications in Settings → Battery → Optimization.

Signs that the battery needs to be changed urgently:

• The phone will run out in 2-3 hours with normal use.
• The charge jumps (for example, from 50% to 20% at once).
• The device overheats or turns off when charging.
• The phone body was deformed (battery bloating).

If the problem persists, the battery controller may have been damaged.