How to check the capacity SIM-Xiaomi Redmi cards: the full guide

Owners of smartphones Xiaomi and Redmi often face the need to assess the state of the smartphone SIM-card, especially when there are problems with registering in the network or displaying contacts. However, the term "capacity" in the context of a SIM card can be misleading, since it is not about battery charges, but about the amount of memory for storing a phone book and the amount of storage of the phone book. SMS-Modern shell-based devices MIUI HyperOS provides advanced diagnostic tools, but access to them is not always obvious to the average user.

Checking the actual amount of available memory on the chip is necessary in situations where you are transferring contacts from an old phone or when the system reports a SIM card storage overflow.

It is important to understand that the standard SIM-The cards have a limited resource, which varies depending on the chip generation (from 32 KB to 256 KB or more).

In this guide, we will go into detail about software and hardware verification methods, as well as ways to optimize your communication module’s memory usage.

The concept of SIM-card capacity in the context of Xiaomi

When we talk about capacity checking on Xiaomi devices, we mean two main parameters: the physical memory capacity of the chip and the current number of occupied cells. Unlike the internal memory of a smartphone where applications and photos are stored, the SIM card memory is reserved exclusively for network identifiers, contacts and text messages.

The Android system on Redmi often hides detailed technical information about the chip, providing only basic data about the operator and signal level, but the company's engineers have provided hidden menus and engineering codes to allow you to look deeper.

⚠️ Note: Do not try to format yourself SIM-a card through an engineering menu if you are not sure of your actions, as this can lead to the complete loss of the contacts recorded on the chip without the possibility of recovery.

There are several types of memory within the module: EF (Elementary File) for contacts, SMS for messages and system files for encryption keys, each partition requires a different approach and level of access to the system.

Using the Engineering Menu for Diagnostics

The most reliable way to access hidden SIM card options on Xiaomi is through the use of an engineering menu, a specialized interface designed to test hardware and view detailed statistics.

To enter the diagnostic menu, you will need to enter a special code in the Phone app. Most Redmi models use universal code ##4636#. Once you enter the last characters, the menu will open automatically, without the need to press the call button.

The menu that opens will select Phone Information, which displays the current connection, but for a detailed capacity check, you often need to go to advanced settings or use third-party utilities if the standard MIUI interface restricts access.

Some users note that new versions of HyperOS firmware have access to the full log. SIM-The card may be restricted for security purposes, in which case the system will only show the basic status of "Connected" or "Disconnected».

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If the ##4636### code doesn’t work, try installing the Activity Launcher app from Google Play, searching the “Phone Information” list, and running it manually.

Checking through standard Android settings

A safer and more affordable method that doesn't require code entry is to use the operating system's standard settings, which allow you to estimate the memory load with contacts and messages, which indirectly indicates the available capacity.

Go to the Settings section → The phone. → All specs → Status SIM-Here you will see the general state of the module. To check the exact amount of memory contacts follow the path Contacts. → Settings → Import/Export of contacts → Copy with SIM-map.

When copying, the system often displays the progress bar with the total number of records available (e.g. 250/500), which is the actual capacity of your SIM card’s phone book.

• 📱 Go to the Contact App on your Xiaomi.
• ⚙️ Click on three dots in the corner and select Settings».
• 💾 Select the option “Contact Management” or “Import/Export».
• 📋 Click on “Copy Contacts” to see the cell limit.

A similar procedure can be performed for SMS. Go to the messages, open the settings and find the item "Management" SIM-The number of free and occupied messages will be indicated.

Third-party analytical applications SIM-map

If the built-in MIUI doesn't give you the full picture, specialized applications from the Google Play store come to the rescue, and they can read the ATR (Answer To Reset) string and other technical parameters of the chip.

One popular tool is the Info SIM Card or Cell Info Lite app, which asks for permission to access the phone's status and provides a detailed report.

Using third-party software allows you to see not only the volume, but also the chip manufacturer and security protocol version, which is especially useful in diagnosing problems with roaming or 4G/5G networks.

But remember that no application can programmatically increase the physical memory capacity of a SIM card, and if the chip is old and small, programs will only state this fact.

Interpretation of results and memory types

Once you get the memory data, it’s important to interpret it correctly: Older Mini-SIM SIM cards often had a 32KB capacity, which allowed you to store about 150-200 short name contacts.

Modern Nano-SIM and USIM cards, which are used in Xiaomi Redmi, usually have a volume of 64 KB to 256 KB. This allows you to store up to 1000 contacts, but the length of the name can be limited to 15-20 characters.

⚠️ Note: If the system tells you that the memory SIM-The card is full, although you see vacant cells, perhaps the problem is in the encoding of names or the length of numbers that take up more space than the standard provides.

Also, it is worth considering that some of the memory is reserved for the operator's needs and is not available to the user, so the actual number of records available is always slightly less than the theoretical maximum.

The key is understanding the difference between SIM memory and phone memory: Contacts saved in a Google account or on a device don't take up space on the SIM card, which is a more modern and reliable approach.

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Memory. SIM-Maps are limited and outdated as the primary contact repository; it is recommended to use Google Cloud Sync to save data.

Optimization and transfer of contacts

If the check showed that the capacity of your SIM card is at the limit, the most reasonable solution is to transfer all data to the internal memory of the smartphone or to the cloud service, which will speed up the device and secure the data.

To perform the transfer to Xiaomi go to Contacts → Settings → Import/Export of contacts → Copy with SIM-Select all contacts and select the location of the Google account or device memory.

After a successful copy, it is recommended to delete all entries from the SIM card to make room for temporary use or backup numbers.This will also solve the problem of "overflow" if it interfered with the reception of new SMS.

• 🔄 Open the Contacts app on Redmi.
• 🗑️ Select the option to delete contacts with SIM».
• ☁️ Make sure all numbers are saved to Google.
• ✅ Check the synchronization in the account settings.

Regular cleaning of SIM card from unnecessary entries prolongs its life and reduces the risk of errors when reading data by the phone module.

Frequent problems and their solution

During the verification process, users may encounter errors such as “Can’t read contacts” or “Can’t read contacts «SIM-This is often due to contact oxidation or software failure.

The first step should always be to reboot the device. If that doesn't work, try removing the tray, wipe the SIM card contacts with a soft cloth and paste back in. Make sure the card sits tight.

In conclusion, checking the capacity of the SIM card on Xiaomi Redmi is a useful procedure for diagnosing contact and messaging problems. Using built-in tools and understanding the limitations of technology, you can effectively manage your data.