How to accurately measure the brightness of the screen on Xiaomi smartphones: from calibration to professional tests

Screen brightness is one of the key parameters affecting smartphone comfort. - Xiaomi devices (including the Redmi line, POCO and Mi) this figure may vary not only from model to model, but also depending on the firmware versions. MIUI. Many users face problems: too dim display in the sun, uneven backlight or inflated brightness values that quickly land the battery?

In this article, we will discuss 5 Proven methods – from standard tools MIUI You'll learn how to measure the brightness in the filaments (cd/m²), Compare it to the manufacturer's stated specs and even calibrate the screen if it's not ideal, and why some Xiaomi models may have a real brightness that's different than the specifications on the screen. 20–30% (And how to fix it).

If you notice that your Xiaomi 13 Ultra or Redmi Note 12 screen is dimmer than before, or want to check if the display matches the stated 1200 nits – this is the guide for you. We will not limit ourselves to superficial tips like “look in the settings”, but dive into technical details: from analyzing sensor data to using color profiles.

Why it’s important to check the brightness of Xiaomi’s screen

The brightness of the screen directly affects three key aspects of smartphone use:

• 🔋 Autonomy: Excessive brightness is one of the main reasons for the rapid discharge of the battery. POCO F5 at a maximum of 1000 nits, the battery goes down 30-40% faster than at 400 nits.
• 👁️ Eye health: Long-term use of screens with brightness above 300 nits during the dark can cause eye fatigue and disrupt sleep. MIUI There is a "Read" mode, but it does not always adjust the backlight correctly.
• ☀️ Sun Visibility: Many Redmi budget models (e.g. Redmi) 10A) have a stated brightness of 400 nits, but in practice it barely reaches 350 nits, making the screen almost unreadable in bright lighting.

Also, not all Xiaomi screens are the same. 12T Pro is equipped AMOLED-Display with peak brightness of 900 nits, and Redmi Note 11 Pro+ — AMOLED But even within the same model, there can be differences because of the production, if you buy a smartphone with your hands or notice that the screen has become dimmer after the upgrade. MIUI, Brightness check will help to identify the problem.

Another nuance: adaptive brightness in Xiaomi often works incorrectly. The light sensor can malfunction, causing the screen to spontaneously dim or, conversely, become too bright. This is especially true for devices with a high-resolution lighting system. MIUI 14 and newer, where adaptation algorithms have become more aggressive.

Method 1: Integrated MIUI tools

Let’s start with the simplest – standard settings. MIUI. This method will not give exact values in the filaments, but will help to estimate the current brightness and compare it with other devices.

How to check the current brightness in MIUI:

1. Open the Settings → Display.
2. Find the "Brightness" slider. MIUI 14 and later next to it is displayed percentage value (for example, 60%).
3. Activate the Adaptive Brightness switch if it is switched off and watch how the backlight changes when the lighting changes.

What can be learned in this way:

• 📊 Percentage of current brightness to maximum (but not real filaments!).
• 🔄 Does adaptive adjustment work (if the slider moves itself when the lighting changes).
• ⚡ Estimated energy consumption: the higher the percentage, the faster the battery discharges.

Limitations of the method:

⚠️ Attention: Percentage scale in MIUI For example, 50% of the brightness on the Xiaomi 13 can correspond to 300 nits, and on the Redmi 9 it can only be 200 nits (AMOLED vs IPS) and manufacturer calibration.

To get more accurate data, we move on to the following method.

Method 2: Applications for measuring brightness

For accurate measurement of brightness in the filaments (cd/m²) You'll need third-party apps, and they use a smartphone's light sensor or calibrated tests to give you objective results.

Top.-3 apps:

Step-by-step instructions with Lux Meter (the most accurate option):

1. Install the application and open it.
2. Place the smartphone on a flat surface with the screen up.
3. Press "Calibrate" and follow the instructions. For Xiaomi with AMOLED Choose a profile "AMOLED Display".
4. After calibration, go to the "Lux" tab, where the current values in lux (lx) are displayed (cd/m²), use the formula: Threads = Suites / π For example, if the application shows 1000 Lx, the actual brightness of the screen ≈ 318 thread.

Tips for accurate measurements:

• 🌞 Measure the brightness in a room with uniform lighting (without direct sunlight).
• 📱 Turn off adaptive brightness in settings MIUI pre-test.
• 🔄 Repeat the measurement 2-3 times and take the average value.

What if the values are very different from the stated ones?

⚠️ Note: If the actual brightness is 20% or more below the passport brightness (for example, the POCO X5 Pro claimed 500 nits, and the measurement shows 350 nits, this may indicate: 🔧 Failure of the illumination or plume of the screen. 📉 Firmware failures (especially after updates) MIUI). 🛠️ Incorrect calibration of the light sensor, in such cases, it is recommended to reset the screen settings or contact the service center.

Method 3: Test images and online services

If you don't want to install apps, you can use online tests or special images to check the brightness, which is less accurate, but helps you visually assess the quality of the backlight.

How to check the brightness without applications:

1. Open the Lagom test in the browser LCD (section "Contrast" or "Black level").
2. Set the brightness of the screen to 50-70% and see if all shades of gray are discernible. AMOLED-screens (for example, Xiaomi 13) should be visible all transitions, IPS (Redmi 10 – possible debris in dark colors.
3. Compare your screen to your reference photos. RTINGS There is a gallery of tests for smartphones, which shows the brightness at different settings.

What can be revealed in this way:

• 🖥️ Uneven lighting: On IPS-screens often show "clouds" or yellowness around the edges.
• 🌑 Quality of black: On AMOLED The black should be perfectly black (pixels off) IPS — greyish.
• ☀️ Maximum brightness: If at 100% tuning test white fields appear dim, the screen falls short of the claimed threads.

Example of a test image to check brightness:

In this image, the white background should be uniformly bright without shades, and if there are gray or yellowish stripes on the edges, this is a sign of backlight problems.

💡

If you AMOLED-screen (Xiaomi) 12/13, POCO F4), Try to turn on the "Dark Theme" mode in MIUI And then we do it again, and in this mode, the black pixels are completely turned off, which increases contrast and subjective brightness.

Method 4: Engineering menu and hidden settings

For advanced users, there's a way to check brightness through Xiaomi's engineering menu, and you can see the real values that the system transmits to the display, including the light sensor.

How to open the engineering menu on Xiaomi:

1. Open the Phone app and enter the code: ##4636###
2. In the menu that appears, select "Phone Information".
3. Scroll down to the Sensors section and find the Light sensor, which shows the current values in the suites.

How to interpret the data:

• 📊 Value - current illumination in the suites, which is recorded by the sensor.
• 🔄 If this value does not change when the outside light changes, the sensor is faulty (a common problem after falls or moisture hits).
• 💡 In some firmware MIUI The current brightness of the screen is displayed in percentage ("Brightness").

Alternative code for new models (MIUI 14+):

##6484##

This code opens the menu "MIUI Display Test, where you can check it:

• 🎨 Screen color scheme.
• 🔦 Maximum brightness (White Screen test").
• 🔍 Sensor sensitivity.

⚠️ Warning: Do not change the settings in the engineering menu unless you are sure of their purpose! Incorrect settings can lead to malfunctions in the screen or sensors. For example, changing the persist.sys.brightness value can make the display too dim or bright without the ability to return settings through the standard interface.

💡

The engineering menu allows you to see real data from the sensors, but it's dangerous to change the parameters without knowing the consequences. Use it only for diagnostics!

Method 5: Professional tools (luxmeter)

If you want the most accurate data (for example, for comparison with specifications or before selling a smartphone), it is better to use a hardware luxmeter. This device measures the illumination in the lux, and then the values are translated into threads.

How to measure the brightness of a luxmeter:

1. Place the smartphone on a flat surface with the screen up.
2. Turn on the white image (you can open an empty document in Google Docs or use the test photo from the previous section).
3. Set the brightness to 100% and turn off adaptive adjustment.
4. Bring the luxmeter to the screen at a distance of 1-2 cm and record the readings in luxes (lx).
5. Translate the luxes into threads by formula: Threads (cd/m²) = Suites (lx) / π For example, 1500 lx ≈ 477 thread.

Recommended Luxmeters for Smartphones:

• 📏 Dr.meter LX1330B — budgetary option with error ±5%.
• 📊 TENMARS TM-207 — calibration.
• 💡 Extech LT300 — Compact and accurate (used in service centers).

When to use a luxemeter:

• 🔧 To diagnose screen malfunctions (for example, after changing the display).
• 📈 For comparison of brightness of several devices (for example, when choosing between Xiaomi 13 and X-rays). POCO F5).
• 🛠️ To calibrate the screen after firmware or repair.

Example of practice:

User Redmi K50 Gaming noted that after the update to MIUI The 14th screen got dimmer. Luxmeter measurements showed:

• Update: 1800 lx (≈ 573 nits) at 100% brightness.
• After update: 1200 lx (≈ 382 nits).

It turned out that the firmware reset the color profile settings to "Standard" instead of "Saturated", which reduced the maximum brightness, and after returning the previous settings, the problem disappeared.

How to Calibrate Brightness on Xiaomi

If the measurements show that the brightness is far from ideal, you can calibrate it manually, which is especially true for devices with a light-based lighting system. AMOLED-screens where color balance often gets lost after updates.

Calibration methods:

1. Reset screen settings: Go to Settings → Display. → Select "Reset Color Settings" (in some versions) MIUI This paragraph is called "Restore by default").
2. Manual Color Profile Adjustment: In the same screen settings, find "Color Scheme". AMOLED Choose "Saturated" (maximum brightness) or "sRGB" (more natural colors).
3. Calibration through the engineering menu (for power users): Open the engineering menu (code ##6484##). Go to Display and find the settings. brightness_mode and backlight_level. Adjust the values carefully, but do not exceed the maximum permissible for your model (can be found in the technical documentation).

What if calibration doesn’t help?

• 🔄 Update the firmware: In new versions MIUI Frequently fix brightness bugs. Check the updates in Settings → The phone. → Updating the system.
• 🛠️ Reset to factory settings: This will help if the problem is caused by an application or setting conflict.Be sure to back up!
• 🔧 If the screen is physically damaged (for example, after a fall), you may need to replace the plume or matrix.

💡

Some Xiaomi models (such as the Mi 11 Ultra) have a hidden “Super Brightness Mode” feature that temporarily increases the brightness to 1200-1500 nits. To activate it, turn on the Battery mode in the settings and set the brightness to maximum in bright light.

Frequent brightness issues on Xiaomi and their solutions

We will analyze the typical complaints of users and ways to eliminate them.

If nothing helps:

Some models (e.g. Redmi Note 10 Pro) have a hardware defect in the backlight controller that occurs after 1-2 years of use, in which case the screen can dim even at 100% brightness, the only solution is to replace the display control board.

FAQ: Answers to Frequent Questions