Screen Test

Q: I found a dead pixel — can I get a replacement?

Under most makers’ policies, up to 3 dead pixels count as normal. But some premium brands (Dell UltraSharp, EIZO) promise a zero-bright-dot guarantee. Test a new monitor immediately and contact support within the return window.

Q: Is IPS backlight bleed normal?

Mild IPS Glow is a physical trait of IPS panels and is almost impossible to avoid. Severe edge bleed that visibly hurts dark scenes at normal brightness and distance is a quality-control issue and can be exchanged.

Q: Why can’t I enter fullscreen?

Some browsers restrict the fullscreen API. Use the latest Chrome/Edge/Firefox, allow fullscreen permission, and trigger it by clicking the button on the page. Even without fullscreen, the test continues in a window.

Q: Will the test damage my screen?

No — the tool only displays patterns and colors, which cannot hurt a display. That said, leaving an OLED on a solid white frame for very long can accelerate ageing, so keep each test under a minute.

Q: I see obvious banding in the grayscale test — why?

It usually comes from a shallow panel color depth (6-bit dithered to simulate 8-bit), a wrong output bit-depth in the GPU driver, or insufficient interface bandwidth. Set 8-bit/10-bit full-range output in the driver and use HDMI 2.0+ or DP 1.4+.

Q: Can I use it on a phone or tablet?

Yes — just open the page. Landscape orientation and higher brightness help, and since mobile screens are small you can use the system zoom when hunting dead pixels.

8 checkups in one tool to assess your monitor and spot dead pixels, bleed or tint.

▶ Run the full screen check

Start with the solid-color test, then work through all 8 checks in order. Click the screen or press Space to move to the next test project. a total of 32 steps

💡 Operation tips

Click the right half of the screen to move to the next view; when the current project’s views are done it advances to the next project, and when every project is finished it exits fullscreen automatically.
Click the left half of the screen to go back to the previous view; at the very first view it stops.
After entering fullscreen, the top label and bottom buttons auto-hide after 3 seconds so you can view the screen unobstructed.
Hover in the bottom-centre of the screen for 1 second to bring the label and buttons back; move away and they hide again after 1 second.
The breathing test ends automatically after about 10 seconds.

{"mode":"base","basePath":"/screen","dict":{"mode":{"base":"All","purecolor":"Pixels","backlight":"Backlight","interference":"Interference","focus":"Focus","contrast":"Contrast","grayscale":"Grayscale","saturation":"Saturation","breathing":"Breathing"},"startAll":"Run the full screen check","startAllSub":"Start with the solid-color test, then work through all 8 checks in order. Click the screen or press Space to move to the next test project.","startSub":"Start test","stepLabel":"a total of {n} steps","fullscreenFail":"Could not enter fullscreen — continuing in windowed mode (patterns still display correctly).","prevView":"Previous view","nextView":"Next view","exitView":"Exit test","nextProject":"Next project","instr":{"purecolor":"Scan the screen for bright, dark or tinted (stuck) pixels. Use the arrow keys to switch colors.","backlight":"Look for light leaking from the edges and corners. Arrow keys toggle between black and gray.","interference":"Watch for moiré, streaks or related interference. Arrow keys switch patterns.","focus":"Check whether text, lines and shapes are crisp and sharp. Arrow keys switch modes.","contrast":"Assess the black-to-white gradient and tonal depth. Arrow keys flip the gradient direction.","grayscale":"Check that the gray steps are smooth with no banding. Arrow keys flip the gradient direction.","saturation":"Judge how vivid and even the saturated colors are. Arrow keys switch between colors.","breathing":"Watch the static gray screen for ~10 seconds and judge whether the brightness pulses periodically."},"colorName":{"black":"Black","white":"White","gray":"Gray","red":"Red","green":"Green","blue":"Blue","yellow":"Yellow","magenta":"Magenta","cyan":"Cyan"},"patternName":{"checkerboard":"Checkers","lines-h":"H-lines","lines-v":"V-lines","grid":"Grid"},"direction":{"left-to-right":"left to right","right-to-left":"right to left","dark-to-light":"black left · white right","light-to-dark":"white left · black right"},"focus":{"large":"Large text","small":"Small text","lines":"Thin lines","grid":"Fine grid","circles":"Circles","largeTitle":"Focus test","smallTitle":"Small-text sharpness","linesTitle":"Thin-line sharpness","gridTitle":"Fine-grid test","circlesTitle":"Circles & curves","vert":"Vertical lines","horiz":"Horizontal lines","diag":"Diagonal lines","fineGrid":"Fine grid (1px)","fineGrid2":"Ultra-fine grid (0.5px)","concentric":"Concentric circles","waves":"Wave lines","largeHint":"Check that large-letter edges are crisp, with no blur or ghosting.","smallBody1":"A paragraph for judging small-text sharpness. Look at whether the letter edges are crisp and the spacing even.","smallBody2":"The quick brown fox jumps over the lazy dog. 0123456789","smallBody3":"Smallest text — gauge readability and clarity at the minimum size."},"breathingTitle":"Breathing test","breathingEnd":"s until it ends automatically","tipsTitle":"Operation tips","tips":["Click the right half of the screen to move to the next view; when the current project’s views are done it advances to the next project, and when every project is finished it exits fullscreen automatically.","Click the left half of the screen to go back to the previous view; at the very first view it stops.","After entering fullscreen, the top label and bottom buttons auto-hide after 3 seconds so you can view the screen unobstructed.","Hover in the bottom-centre of the screen for 1 second to bring the label and buttons back; move away and they hide again after 1 second.","The breathing test ends automatically after about 10 seconds."]}}

Screen tests

Dead / Stuck Pixels : Fullscreen solid colors to hunt bright, dark and tinted pixels. Backlight Test : Detect light bleeding from the edges and corners on black backgrounds. Interference Test : Checker, line and grid patterns to reveal moiré and striping. Focus Test : Text, lines and shapes to check sharpness and sharp edges. Contrast Test : Black-white gradients to gauge tonal depth and smooth transition. Grayscale Test : A stepped gray ramp to check uniformity and banding. Color Saturation : Vivid solid colors to assess gamut coverage and color accuracy. Breathing Test : Watch a static gray screen to judge periodic brightness pulsing.

Why choose My PC Tester?

Install-free, privacy safe

Runs entirely in the browser — nothing to download. Every test runs locally and no screen data is uploaded.

Eight-in-one checking

Dead pixels, backlight, interference, focus, contrast, grayscale, saturation and breathing — a complete screen exam in one place.

Fullscreen immersion

One click enters fullscreen mode, clearing the browser UI so patterns cover every pixel for more accurate results.

Free and easy

Everything is permanently free with no sign-up. Guided tips, arrow keys and shortcuts switch colors and modes easily.

How to start testing

01 · Pick a test
Click “Run the full screen check” or any single sub-test to enter fullscreen; you can also open one test page directly.
02 · Scan the screen
In fullscreen, look over every region and use the arrow keys to switch solid colors, patterns or directions.
03 · Judge the result
Decide whether you spot dead pixels, bleed, tint or other faults. Click the right half to move on, or press ESC to exit.

Screen terms explained

Dead / stuck pixel: A pixel that does not work correctly — bright (always lit), dark (never lit) or tinted (showing a wrong color). ISO 13406-2 defines how many are permitted in each panel grade.
Backlight bleed (BLB): Unexpected light leaking from the edges or corners. Common on IPS panels, shown as white or yellow halos in dark scenes.
IPS Glow: A physical trait of IPS panels — silver-white glow in the corners when viewed from an angle. Unlike bleed it shifts with your viewing angle and is normal.
Contrast ratio: The brightness ratio between the whitest white and darkest black. IPS is typically 1000:1, VA reaches 3000–5000:1, OLED is theoretically infinite.
Color depth: How many gray levels a panel can show. 6-bit shows 262k colors, 8-bit 16.7 million, 10-bit 1.07 billion — deeper depth gives smoother gradients.
Color gamut: The range of colors a screen can display. Common standards are sRGB, DCI-P3, Adobe RGB and Rec.2020 — wider coverage means richer color.
PWM dimming: Adjusting brightness by rapidly switching the backlight on and off. A very low frequency (<200 Hz) can cause visible flicker and eye strain.
Moiré: Interference fringes where two repeating patterns overlap — it can appear with fine patterns and relates to the panel or signal.

Troubleshooting

Dead / bright / dark pixels

Symptom: on solid colors, pixels stay lit, stay off or show a wrong color.

How to fix it:

Use the “Dead pixel” test and check all 8 colors one by one.
Within the return window, screenshot the dead pixels and contact support — some high-end brands guarantee a zero-bright-dot policy.

Backlight bleed

Symptom: obvious halos or bright patches at the edges or corners on a black screen.

How to fix it:

Use the backlight test in a dark room at 30–50% brightness, not maximum, to avoid false positives.
Mild IPS Glow is normal; severe edge bleed (BLB) that hurts normal use is a quality issue — you can ask for an exchange.

Flicker / screen flashing / striping

Symptom: brightness flickers, or horizontal/vertical stripes appear on certain images.

How to fix it:

Can come from low-frequency PWM, a GPU driver issue or a loose cable.
Try raising brightness, updating the GPU driver or swapping the cable; use the interference test to confirm the striping.

Ghosting / trailing

Symptom: obvious smear or trailing in fast-moving scenes.

How to fix it:

Usually slow LCD response time — VA panels are most noticeable.
Turn on the monitor’s Overdrive / Response Time boost, but avoid overdrive that adds reverse ghosting.

Screen care & usage tips

Match brightness to the room

Aim for 120–150 nits for office work and 80–100 nits for dark-room entertainment. Too bright ages the panel and strains eyes; too dim hides shadow detail.

Set a sensible color temperature

6500K (D65) by day; drop to 4000–5000K at night to cut blue light, or use the OS night mode to do it automatically.

Prevent OLED burn-in

Static elements left on an OLED for long periods can leave ghosting. Use pixel shift or a screensaver so the taskbar and logos are not permanently displayed.

Calibrate and clean regularly

Pro users should calibrate color with a hardware probe monthly; clean the screen with a soft cloth and avoid strong direct light. Matte panels suit bright rooms.

Frequently asked questions

I found a dead pixel — can I get a replacement?

Under most makers’ policies, up to 3 dead pixels count as normal. But some premium brands (Dell UltraSharp, EIZO) promise a zero-bright-dot guarantee. Test a new monitor immediately and contact support within the return window.

Is IPS backlight bleed normal?

Mild IPS Glow is a physical trait of IPS panels and is almost impossible to avoid. Severe edge bleed that visibly hurts dark scenes at normal brightness and distance is a quality-control issue and can be exchanged.

Why can’t I enter fullscreen?

Some browsers restrict the fullscreen API. Use the latest Chrome/Edge/Firefox, allow fullscreen permission, and trigger it by clicking the button on the page. Even without fullscreen, the test continues in a window.

Will the test damage my screen?

No — the tool only displays patterns and colors, which cannot hurt a display. That said, leaving an OLED on a solid white frame for very long can accelerate ageing, so keep each test under a minute.

I see obvious banding in the grayscale test — why?

It usually comes from a shallow panel color depth (6-bit dithered to simulate 8-bit), a wrong output bit-depth in the GPU driver, or insufficient interface bandwidth. Set 8-bit/10-bit full-range output in the driver and use HDMI 2.0+ or DP 1.4+.

Can I use it on a phone or tablet?

Yes — just open the page. Landscape orientation and higher brightness help, and since mobile screens are small you can use the system zoom when hunting dead pixels.