Used monitor checklist: tests before buying
Check the actual unit under controlled conditions: model, pixels, motion and connection. Record repeatable observations before buying.
Monitor tests and display troubleshooting guides
Start with the issue you can see, run the matching test and use the guide to avoid common false positives.
Editorial approach and corrections · Testing methodology and limitations
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Buying and first setup
New monitor checklist: what to check after setup
Verify a new display’s setup, pixels and motion. Document repeatable symptoms together with the settings used.
New guides
USB-C dock: no display or low refresh rate? A controlled checklist
No picture or a missing high-refresh mode through a USB-C dock does not, by itself, prove a faulty monitor.
How to photograph a monitor defect for a useful support report
A monitor photo helps locate an observation; it is not an instrument reading of brightness, colour accuracy or permanent damage.
What can an automatic monitor test actually measure?
An automatic monitor test can mean showing patterns in sequence or deciding that the hardware is healthy without observation.
Pixels and panel
Dead Pixel Test
Solid colours make a suspicious dot easier to see; they do not identify its cause by themselves. Use the checks below to distinguish a physical pixel defect from dust, a surface mark or rendered content.
What is dead pixel?
A dark fixed pixel differs from a bright or colour-stuck subpixel.
IPS Glow Test
A black screen is only the starting point. Viewing angle, daily brightness and automatic camera exposure must be controlled before you judge a corner glow or an edge leak.
IPS glow vs backlight bleed
IPS glow generally changes with viewing angle and distance; backlight bleed tends to stay near the same edge.
OLED and near-black test
Inspect desktop WOLED/QD-OLED monitors and AMOLED smartphones for taskbar, HUD, status-bar, or icon burn-in and near-black vertical banding using 8 full-screen diagnostic patterns.
Pixel warranty guide
Model-specific warranty conditions must be verified with the seller or manufacturer.
Motion and clarity
Ghosting Test
Not every moving blur is panel ghosting. Compare a fixed motion pattern and judge dark trails and bright halos separately while keeping refresh rate, zoom and brightness unchanged.
What is ghosting?
Ghosting is a trail that follows a moving object; bright halos can instead be overdrive overshoot.
Screen Tearing Test
Screen tearing is usually a timing mismatch, not a physically cracked panel. It appears when portions of different frames reach the screen during one scan.
Best monitor settings for gaming
Start with the native resolution and the intended refresh rate.
Hz and frame-skipping check
Animation cadence is estimated from requestAnimationFrame timestamps. It is not a direct measurement of the Hz configured in system display settings. Tab visibility, workload and power saving can change the result.
Why is the high refresh rate missing?
A monitor advertised as 165 Hz can still show only 60 Hz on a particular connection.
Colour and tone
monitor calibration basics
Begin with the native resolution and a comfortable brightness in normal room light.
Controlled checks for blurry text
When letters look soft, pushing monitor sharpness to its maximum is not a useful first response.
Why does HDR look washed out on the desktop?
A desktop becoming dimmer or less saturated after enabling HDR does not automatically establish a faulty monitor.
Why do monitor test results change?
A problem appearing in one test but not another does not automatically mean the test is broken or the monitor is faulty.
Tools and report
Cable bandwidth calculator
If your monitor only shows 60 Hz or 120 Hz instead of 144 Hz, 165 Hz, or 240 Hz, the bottleneck is often the HDMI or DisplayPort interface generation.
PPI and screen-size comparison
Screen size alone does not describe how finely pixels are packed.
Monitor test report
Check a new or used monitor in a repeatable order, collect your observations in one place and export a text file or use your browser's print dialog to create a PDF.
Monitor symptom checker
If something looks wrong but you do not know its name, start with what you can see.