How to check the battery capacity on Android: from standard settings to the engineering menu

Battery capacity is a key parameter that determines how long your smartphone will work without recharging. Over time, the battery wears out: after 300–500 charging cycles, its actual capacity may decrease by 20–30%. But how can you find out the current state? Manufacturers rarely show this information in the standard interface, and data from the settings often display nominal capacity (declared by the factory), and not the actual.

In this article we will analyze 5 working methods - from simple (through phone settings) to advanced (using ADB and engineering menu). The methods are suitable for devices Samsung, Xiaomi, Realme, Honor, Google Pixel and other brands based on Android 10–14. You will learn how to check the capacity without root access, which applications provide accurate data, and what to do if the phone shows incorrect values.

Important: some methods require technical knowledge. If you are not sure of your actions, skip the sections with ADB or the engineering menu - they are intended for experienced users.

1. Checking through standard Android settings

The easiest way is to look at the battery menu. Unfortunately, not all manufacturers display the actual capacity there, but it’s worth a try. The instructions are relevant for Samsung Galaxy (One UI), Xiaomi/Redmi/Poco (MIUI), Google Pixel (pure Android) and some models Honor.

How to check:

• 📱 Samsung: go to Settings → Device care → Battery → Settings (⚙️) → Battery status. The wear percentage or current capacity may be displayed here (for example, "2800 mAh out of 3000 mAh").
• 📱 Xiaomi/Redmi/Poco: open Settings → Battery → Battery status. On some models (for example Redmi Note 12) the exact value in mAh is shown.
• 📱 Google Pixel: in Settings → Battery → Battery settings (⚙️) sometimes there is a "Battery status" item with wear data.
• 📱 Others brands: if there is no information about capacity in the battery settings, try entering the code in the phone dialer ##4636## (an engineering menu with battery data will open).

⚠️ Attention: On some firmware (especially custom ones), standard settings may show nominal capacity instead of real. For example, if the factory states 4000 mAh, the phone will display this value even if the wear level is 50%. To obtain accurate data, use the methods in the following sections.

2. Applications for checking battery capacity (without root)

If there is no battery data in the settings, install a specialized application. We tested 10 apps and selected 3 of the most accurate:

Application	Accuracy	Additional functions	Cons
AccuBattery	⭐⭐⭐⭐	Tracks charging cycles, temperature, discharge rate	Requires calibration (several charging cycles)
Battery Guru	⭐⭐⭐	Shows voltage, battery technology (Li-ion/Li-Po)	Advertising, sometimes inflates values
CPU-Z	⭐⭐⭐	Displays battery model, voltage, temperature	The capacity is not shown on all devices

How to use AccuBattery (the most reliable option):

1. Install the application from Google Play.
2. Connect the phone to charge and wait until 100%.
3. Turn off charging and use the phone up to 20–30%.
4. In the section Health an estimate of the actual capacity will appear (for example, "3200 mAh out of 4000 mAh").

💡 Helpful tip: For accuracy, repeat the charge-discharge cycle 2-3 times. AccuBattery analyzes the data and adjusts the indicators.

Charge the phone to 100%|Disable battery optimization for the application|Do not use the phone while charging|Repeat the cycle 2-3 times-->

3. Checking through the engineering menu (codes and hidden settings)

Manufacturers hide technical information in the engineering menu. It can be accessed through special codes or button combinations. Caution: Do not change the parameters in this menu if you are not sure of their purpose!

Ways to open the engineering menu:

• 📞 Universal code: enter in the dialer ##4636##, select Battery information. The charge level, voltage, temperature and sometimes capacity are displayed here.
• 📞 For Samsung: code *#0228# shows voltage, temperature and current charge in mAh (but not full capacity).
• 📞 For Xiaomi: code ##6484## opens the test menu, where in the section Battery there may be information about the capacity.
• 🔧 For Huawei/Honor: code ##2846579##, then select ProjectMenu → Background Settings → Battery.

⚠️ Attention: On some firmware the engineering menu may be missing or require superuser rights (root). If the code does not work, proceed to the next method.

What to do if the engineering menu does not open?

If the codes do not work, the reasons may be as follows:

1. The manufacturer has blocked access (relevant for new models Samsung i Xiaomi).

2. Custom firmware has been installed that has removed the engineering menu.

3. The phone is blocked by the operator (for example, broken devices from MTS or Beeline).

In this case, use the methods with ADB or applications from section 2.

4. Checking through ADB (for experienced users)

ADB (Android Debug Bridge) - a debugging tool that allows you to obtain data directly from the system. This method works on most devices, but requires connection to a computer.

What you will need:

• 💻 Computer with Windows/macOS/Linux.
• 📱 USB cable (preferably original).
• 🔧 Installed drivers ADB (you can download from the official Android website).
• 🔲 Enabled USB debugging on the phone (Settings → About phone → Number assembly — press 7 times, then return to Settings → System → For developers → USB debugging).

Instructions:

1. Connect the phone to the computer and confirm access to debugging on the smartphone screen.
2. Open the command line (Windows) or Terminal (macOS/Linux) and enter:

adb shell
dumpsys battery

3. In the output, find the lines:
   • capacity: X — current charge in percentage.
   • charge_counter: Y —current capacity in mAh (divide by 1000 to get mAh).
   • voltage: Z —voltage in millivolts.

To find out full capacitycharge the phone to 100% and run the command again. Value charge_counter at 100% charge ≈ real capacity.

🔍 Output example:

Current Battery Service state:
AC powered: false
USB powered: true
Wireless powered: false
status: 2
health: 2
present: true
level: 85
scale: 100
voltage: 4123
temperature: 290
technology: Li-ion
  charge_counter: 2850000  ← this is 2850 mAh

5. Verification with root access (maximum accuracy)

If your phone has root access, you can get the most accurate information about the battery. Root provides access to system files where the actual capacity, number of charging cycles and other parameters are stored.

Checking methods:

• 📄 Via file /sys/class/power_supply/battery/capacity: use any file manager with root access (for example, Root Explorer) and open file. It contains the current capacity in mAh.
• 📊 App Battery Monitor Widget: shows discharge graphs, actual capacity and even predicts battery life.
• 🔧 Command in Terminal Emulator: enter cat /sys/class/power_supply/battery/charge_full - this value ≈ full capacity.

⚠️ Attention: Root access will void the warranty and may lead to unstable operation of the phone. If you are not an experienced user, it is better to use the non-root methods from the previous sections.

💡 Useful advice: After obtaining root access, install AccuBattery Pro - it will show exact number of charging cycleswhich will help predict the remaining battery life.

6. Estimation of capacity based on operating time (indirect method)

If none of the above methods worked, you can approximately estimate the capacity based on battery life. This method is not accurate, but it will help you understand how worn out the battery is.

How to check:

1. Charge the phone to 100% and turn off charging.
2. Turn on airplane mode to exclude the influence of the network.
3. Run the test: reproduce video in a loop (from the screen, without sound) or use the application CPU Burn-in for the load.
4. Take the time during which the charge drops to 20%.
5. Compare with the reference values for your model (for example, Samsung Galaxy S23 in such a test it should work for ~8 hours with a capacity of 3900 mAh).

📊 Approximate standards for popular models:

Model	Nominal capacity	Working time in the test (video, airplane mode)	With 30% wear, the time is reduced to
Xiaomi Redmi Note 12	5000 mAh	~10–12 hours	7–8 hours
Samsung Galaxy A54	5000 mAh	~9–11 hours	6–7 hours
Google Pixel 7	4355 mAh	~7–9 hours	5–6 hours

⚠️ Attention: The result is influenced by background processes, screen brightness and temperature. For accuracy, repeat the test 2-3 times and average the values.

7. What to do if the battery capacity has greatly decreased?

If the test shows that the actual capacity is 30–50% lower than the nominal capacity, the battery requires replacement. Here's what you can do:

• 🔄 Calibration: sometimes it helps to reset the battery controller. Charge the phone to 100%, then discharge to 0% and charge again to 100% without interruption.
• 🛠️ Battery replacement: contact the service center. Replacement cost for popular models:
  • Samsung Galaxy S23: ~3 500–5 000 ₽.
  • Xiaomi Redmi Note 11: ~2 000–3 000 ₽.
  • iPhone (unofficial service): ~4 000–7 000 ₽.
• 📉 Optimization: If replacement is not an option, reduce the load:
  • Disable background activity of applications.
  • Use a dark theme and lower the screen brightness.
  • Turn on power saving mode.

💡 Helpful advice: Before replacing the battery, check it for authenticity. Counterfeit batteries (especially for Samsung and iPhone) often have a capacity 20-30% lower than declared.

💡

If after replacing the battery the phone discharges quickly, check the power consumption in Settings → Battery. A faulty application or background processes may be to blame.

FAQ: Frequently asked questions about battery capacity

🔋 How often should you check the battery capacity?

Optimally - once every 3–6 months. If your phone begins to discharge quickly, check the capacity immediately. Lithium-based batteries (Li-ion/Li-Po) lose ~20% of capacity over 2-3 years of active use.

📉 Why do applications show different capacities?

Applications estimate capacity differently:

• AccuBattery analyzes cycles charging.
• CPU-Z takes data from system files (sometimes outdated).
• Engineering menu shows the current charge, not the full capacity.

The most accurate method is ADB or verification with root access.

🔌 Is it possible to restore the battery capacity?

No, it is impossible to restore a worn-out battery. All “miracle methods” (freezing, flashing the controller, special charging) are a myth. The only way out is to replace it with a new battery.

⚡ How to properly charge your phone to maintain capacity?

Follow the rules:

• Avoid complete discharge (keep the charge in the range of 20-80%).
• Do not use cheap chargers (they overheat the battery).
• Do not leave the phone on charge overnight.
• Avoid overheating (do not play games heavy games while charging).

Modern smartphones (for example, Samsung Galaxy S23 Ultra) have built-in protection against overcharging, but these measures will extend the service life.

📱 Why does a new phone show a capacity lower than declared?

This is normal. Manufacturers indicate nominal capacity (for example, 5000 mAh), but the real one may be 5-10% less due to:

• Production errors.
• Wear margin (battery designed for 400–500 cycles).
• System energy consumption (part of the charge is spent on background processes).

If the difference is more than 15%, this is a reason for a return under warranty.