Online Screen Check · Screen Test · Monitor Test

Screen Test - Online Screen Check and Monitor Test

Screen Test is a comprehensive tool for online screen check and monitor test through your browser, helping you quickly troubleshoot hardware and panel faults such as dead pixels, backlight bleed, color distortion, and insufficient contrast. It integrates solid color, line, contrast, gradient, and saturation tests, featuring full-screen highlight, millisecond-level switching, and precise color block analysis, supporting dead pixel test, backlight bleed test, and color gamut test. Open the page to start a complete and objective screen check, providing a reliable basis for second-hand monitor acceptance and post-repair quality verification.

Click the Start Test button, use ← and → to switch screen tests

Solid Test

Lines Test

Pattern Test

Gradient Test

Contrast Test

Other Test

More Professional Screen Test Tools

From solid colors to gradients, covering every detail of dead pixel test, backlight bleed test, color gamut test, and monitor test

Ghosting TestDetect screen ghosting level and response time through motion graphics and afterimage comparison, determining dynamic image clarity HDR TestDisplay high dynamic range test patterns to detect HDR display performance, brightness levels and color gradient transitions Screen Tearing DetectionDisplay high-speed motion images to detect screen tearing, vertical sync issues and frame rate stability Backlight Bleed TestObserve edge glow on pure black screens to detect backlight bleed level and backlight uniformity Color Gamut DetectionDisplay standard color gamut test patterns to detect screen color reproduction, gamut coverage and color accuracy Screen Size CalculatorCalculate screen size, display area and pixel density based on resolution and diagonal, assisting with monitor purchasing Dead Pixel TestProvide multiple solid color backgrounds to detect dead pixels, bright pixels, dark pixels and abnormal colored pixels Burn-In TestDisplay afterimage test patterns to detect screen burn-in, image retention and pixel aging

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In-depth Understanding of Screen Test

Professional monitor test and panel analysis tools to help you quickly diagnose screen faults

What is Screen Test?

Screen Test, also known as monitor test or online screen check, is a tool that directly checks screen panel and display performance through a browser without installing any software. When you switch test images, it immediately displays test patterns such as solid colors, lines, grids, and gradients in full screen or specified areas, while supporting full-screen mode and keyboard shortcuts. This screen test method is suitable for LCD, LED, OLED, CRT as well as laptop screens, external monitors, and various other display devices. It is the preferred method for quickly troubleshooting screen faults.

Unlike traditional hardware detection tools, screen test runs entirely locally. Image switching and operation data are not uploaded to the server, fully protecting privacy. Simply open the webpage to perform dead pixel test, backlight bleed test, contrast test, and color test. This tool provides six core test modes: Solid Color Test (white, red, green, blue, yellow, cyan, magenta, black, for dead pixel test and backlight bleed test), Line Test (horizontal lines, vertical lines, diagonal lines, dot matrix, checking geometric distortion and basic screen check), Pattern Test (micro patterns, flashing blocks, square grids, color grids, assisting monitor test), Contrast Test (dark field and bright field grayscale, evaluating screen contrast performance), Gradient Test (smooth transitions of white, red, green, blue, detecting color smoothness and color gamut test), Saturation Test (color saturation and color cast detection, a key item in screen check). In daily use, screen check usually focuses on five aspects: dead pixels, backlight bleed, contrast, color smoothness, and geometric distortion. Through solid color tests and contrast tests, you can quickly distinguish between panel defects and signal interference, while line and grid tests are used to verify the monitor's geometric accuracy and signal stability. Through this convenient screen check, you can quickly locate problem areas, providing a basis for subsequent repair or replacement.

How to Perform Dead Pixel Test?

Dead pixels are pixels on the screen panel that permanently maintain one color, which can be bright dots (white) or dark dots (black). This tool provides a Solid Color Test including eight colors: white, red, green, blue, yellow, cyan, magenta, and black. By switching through solid color screens, you can carefully check whether there are any points with abnormal colors on the screen. It is recommended to check in a darker environment, 30-50 centimeters from the screen, carefully examining each color one by one.

When performing a dead pixel test, pay attention to distinguishing between dust and dead pixels: dust can be wiped off, dead pixels cannot. If a fixed color point is found, you can try applying gentle pressure or using pixel repair software, but physical dead pixels usually cannot be recovered. For second-hand monitor acceptance, dead pixel test is an essential step. Additionally, pure black screen can also be used for backlight bleed test to observe whether there is uneven halo around the screen edges.

How to Judge Screen Quality Through Contrast Test?

Contrast refers to the ratio between the brightest and darkest parts of a screen, directly affecting image layering. This tool provides Contrast (Dark) and Contrast (Bright) tests. By displaying color blocks of different grayscale levels, you can observe whether the screen can distinguish similar grayscale levels. Typically, professional monitors can distinguish more grayscale levels, while ordinary monitors may not be able to see the boundaries of the last row (brightest or darkest) of color blocks.

Besides contrast, the Gradient Test is used to check whether color transitions are smooth, and the Saturation Test is used to observe color vividness and whether there is color cast, assisting in color gamut test. Line and grid tests are used to check the monitor's geometric distortion and signal stability. If further testing of motion blur, response time, or brightness range is needed, you can combine ghosting test, HDR test, refresh rate test, and monitor resolution calculation for comprehensive evaluation. Regularly performing screen tests can detect panel aging, uneven backlight, color drift, and other issues in advance, making it evidence-based when choosing or adjusting a monitor.

How to Use the Screen Test Tool

Open the page and enter the screen test area

Click the "Start Test" button or scroll directly to the tool area, select the test mode you need (default is pure white), and start the online screen check and monitor test.

Switch test screens and carefully check dead pixel test and backlight bleed test

Use left canvas clicks, keyboard ←/→ keys, or the scroll wheel to quickly switch test patterns. It is recommended to check in full-screen mode (press F key) to avoid interference and complete the screen check.

Record issues and judge monitor test results

When dead pixels, backlight bleed, color abnormalities, or geometric distortion are found, you can pause and mark them. If the problem is obvious, it is recommended to contact after-sales service or consider replacing the panel.

Basic Knowledge Related to Screen Test

1. Screen types and testing points: Mainstream screens on the market are divided into LCD (including IPS, VA, TN), OLED, Mini-LED, and older CRT. LCD screens may have backlight bleed and viewing angle issues, so emphasis should be placed on backlight bleed test and contrast test; OLED screens have self-emissive pixels and need attention to burn-in and brightness uniformity, so solid color and gradient tests are recommended; laptop screens and external monitors have different sizes and resolutions, so screen checks should be performed at native resolution, and can be combined with monitor resolution calculation to confirm dot pitch and pixel density. For all types, solid color test and line test can quickly confirm dead pixels and geometric distortion.

2. Dead pixel and bright dot detection (dead pixel test): Dead pixels are divided into bright dots (always on) and dark dots (always off), with some being colored dots (fixed red, green, or blue). Through the screen test tool, switching between pure white, pure black, and pure red, green, and blue screens in sequence can clearly observe abnormal pixels. If the number of dead pixels exceeds the manufacturer's standard, you can apply for replacement. When performing a dead pixel test, pay attention to cleaning the screen surface to avoid dust interference with judgment.

3. Backlight bleed test and brightness uniformity: Backlight bleed mostly occurs in IPS and VA panels. Under a pure black screen, observe whether there are obvious halos or uneven brightness at the screen edges. Through the pure black test, the degree of backlight bleed can be quantified. If the edge halo is too obvious, it indicates poor backlight module assembly or low panel quality. In daily use, appropriately reducing brightness can alleviate backlight bleed, which is also the significance of backlight bleed test.

4. Contrast and grayscale: Contrast is a key indicator of screen layering. Through Contrast (Dark) and Contrast (Bright) tests, observe whether similar grayscale color blocks can be distinguished. If the last row of color blocks cannot be distinguished, it indicates insufficient screen contrast or improper gamma settings, which can be adjusted through the OSD menu or by replacing the monitor. Before performing a contrast test, it is recommended to first confirm via monitor resolution calculation that the monitor is at its optimal resolution.

5. Color and saturation: The Gradient Test is used to check whether color transitions are smooth. If banding or color stripes appear, it indicates insufficient panel color depth or driver setting issues. The Saturation Test can reflect the screen's color vividness and whether there is color cast, and is an important component of color gamut test. Professional design users are recommended to use a color calibrator in conjunction.

6. Geometry and signal stability: Line Test and Grid Test can check whether the monitor has geometric distortion, curved lines, or jitter caused by signal interference. Especially for CRT and analog signal devices, these tests can effectively detect problems. Problems are less common with digital signals (HDMI/DP), but checking is still recommended. For high refresh rate monitors, refresh rate test and ghosting test can be combined to further judge dynamic clarity; HDR test is used to verify high dynamic range performance and can serve as an extended reference for screen check.

Supported Screen Types for Testing

Covering mainstream display devices, accurately completing screen checks regardless of screen type

LCD MonitorIPS / VA / TN

LED MonitorBacklight Type

OLED ScreenSelf-Emissive Pixels

Mini-LED ScreenHigh-Zone Backlight

Laptop ScreenPortable / High Resolution

External MonitorHDMI / DP / USB-C

Professional Graphics MonitorWide Color Gamut / High Color Accuracy

Gaming MonitorHigh Refresh Rate / Low Latency

Featured Articles Related to Screen Test

From beginner to advanced, helping you thoroughly master screen checks and monitor tests

Screen Dead Pixel Test and Backlight Bleed Test: Complete Online Screen Test TutorialHow to use online screen test tools to check for dead pixels, bright pixels, and dark pixels, and determine backlight bleed levels through solid color and dark field images. Includes monitor test steps and common troubleshooting methods.Refresh Rate Test and Ghosting Test: Is Your Monitor Really Smooth?Detailed explanation of monitor refresh rate testing methods, using tools like UFO Test to judge ghosting, afterimage, and response time performance, helping gamers and designers verify screen dynamic display quality.HDR Test and Color Gamut Detection: How to Judge If Screen Colors Meet StandardsIntroduction to HDR test images and video usage, as well as sRGB, DCI-P3, Adobe RGB color gamut detection techniques, helping you evaluate monitor color reproduction and high dynamic range performance.Monitor Resolution Calculation and Online Screen Test Tool CollectionLearn to calculate PPI based on monitor size and resolution, understand the relationship between clarity and viewing distance, and compile commonly used online screen test websites for one-stop screen testing, dead pixel testing, and refresh rate testing.

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Core Advantages of This Screen Test Website

Eight Solid Colors Quick Switch

White, red, green, blue, yellow, cyan, magenta, black—one-click switching makes dead pixel test and backlight bleed test effortless.

Precise Contrast Detection

Finely arranged grayscale color blocks accurately evaluate screen contrast and gamma performance, assisting monitor test.

Privacy First, Local Operation

All screen switching is rendered only locally in the browser, protecting privacy and making online screen checks more reassuring.

Compatible with All Display Devices

LCD, LED, OLED, laptop, and external monitors can all undergo screen checks.

No Installation, Cross-Platform Use

No software download needed. Windows, macOS, Linux, and even mobile browsers can open and run screen tests instantly.

One-Click Full-Screen Mode

Supports F key for full screen, combined with keyboard arrow keys and scroll wheel to quickly switch screen check screens.

Why Choose Online Screen Test?

Testing Method

Desktop SoftwareRequires downloading dedicated software or entering the monitor OSD menu; steps are cumbersome and cannot cover all screen check items.

This ToolOpen the webpage to start an online screen check with built-in test patterns such as solid colors, lines, contrast, and gradients; one-click switching with real-time display.

Dead Pixel Test

Desktop SoftwareMost tools only provide black and white colors, making it difficult to detect colored dead pixels or dark dots.

This ToolProvides eight solid color backgrounds; dead pixel test covers common dead pixel colors, making any abnormal pixel clearly visible.

Contrast Test

Desktop SoftwareRequires manually creating grayscale images or using professional instruments, making it difficult for ordinary users to operate.

This ToolBuilt-in dark field and bright field grayscale test charts with scientifically arranged color blocks; judge screen contrast level at a glance, assisting monitor test.

Geometric Distortion

Desktop SoftwareNo dedicated line and grid tests, making it impossible to quickly detect geometric distortion or signal interference.

This ToolMultiple patterns such as horizontal lines, vertical lines, diagonal lines, dot matrices, square grids, and color grids make geometric problems clear at a glance, supporting screen check.

Privacy Security

Desktop SoftwareDesktop software may collect screen information or operation records, posing privacy risks.

This ToolFully local operation; online screen check data never leaves the device, eliminating information leakage risks from the source.

Frequently Asked Questions About Screen Test

Do screen tests and online screen checks require software installation?

Not at all. This is a pure web-based screen test tool based on native browser rendering and the fullscreen API. Open the page to perform solid color test, contrast test, gradient test, and other online screen checks. All screen switching is done locally, and no personal information is uploaded. Open the browser to complete a full monitor test.

How to judge dead pixel test?

In solid color test mode, switch between white, red, green, blue, yellow, cyan, magenta, and black in sequence, and carefully observe whether there are fixed points (bright or dark dots) on the screen. If a pixel remains the same color under all colors, it is a dead pixel. It is recommended to check in a dark room environment, 30-50 centimeters from the screen. Normal pixels change with color; dead pixels do not. This is the key to judging dead pixel test in screen check.

How should backlight bleed test be viewed?

Switch to a pure black screen and observe in full-screen mode whether there are obvious halos or uneven brightness at the screen edges. Backlight bleed usually appears as whitish or grayish corners or edges. Slight backlight bleed is normal, but if it is severe, it indicates a problem with the backlight module and may affect viewing and gaming experience. OLED screens theoretically have no backlight bleed due to self-emissive pixels. Backlight bleed test is mainly aimed at LCD and Mini-LED screens.

What is the use of contrast test?

Contrast test helps you judge whether the screen can distinguish similar grayscale levels by displaying color blocks of different grayscale. In the Contrast (Dark) test, observe whether the darkest few rows of color blocks can be distinguished; in the Contrast (Bright) test, observe the brightest few rows. If the last row cannot be distinguished, it indicates insufficient screen contrast or improper gamma settings, which can be adjusted through the OSD menu. This is also a basic and important part of monitor test.

What problems can gradient test detect?

Gradient test displays a smooth transition from black to white or red, green, and blue. If obvious color banding, discontinuities, or graininess appear in the image, it indicates insufficient color smoothness of the screen, possibly due to low panel color depth or driver setting issues. Professional design users should focus on this test and combine it with color gamut test to judge color coverage. Use a color calibrator for calibration when necessary.

What are line and grid tests for?

Line test displays horizontal lines, vertical lines, diagonal lines, and dot matrices to check whether the monitor has geometric distortion, curved lines, or jitter caused by signal interference. Grid test displays square grids and color grids to help you confirm whether lines are perfectly horizontal and vertical and whether widths are consistent. If lines are twisted or grids are uneven, it indicates a problem with the monitor's geometric correction or signal synchronization. These tests can also serve as reference prerequisites for monitor resolution calculation, refresh rate test, ghosting test, and HDR test.

Screen issues? Start your screen test now

Screen check, dead pixel test, backlight bleed test, color gamut test, contrast test, gradient test—all in one page.

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