Monitor Test: Free Online Display Test & Screen Test Tools
A complete suite of browser-based monitor test tools. Whether you are checking a brand-new display for defects inside the return window, testing a second-hand monitor before you buy it, or calibrating an old panel that has drifted, pick a tool below — or follow the full testing sequence further down the page.
White Screen Test
The original bright screen testing, reading light, and meditation tool.
Dead Pixel Test - Check Your Screen Online
Detect dead, stuck, or hot pixels on your LCD, LED, and OLED monitors instantly.
Dead Pixel Fixer & Stuck Pixel Fixer
Fix and revive stuck pixels on your display using rapid RGB color flashing patterns.
Monitor Color Calibration Tool
Professional monitor calibration tools to test brightness, contrast, and gamma settings for optimal viewing.
Monitor Color Accuracy Test & Color Checker
Test monitor color accuracy, sRGB gamut reproduction, and true RGB color purity.
Backlight Bleed Test
Check for backlight bleeding, clouding, and IPS glow to ensure perfect screen uniformity.
Computer Monitor Yellow Tint Tester & Fixer
Check your display for yellowish tint discoloration, screen burn-in, or blue light filter issues.
Refresh Rate Test & Screen Hz Tester
Measure your screen Hz and frames per second to check if your monitor runs at 60Hz, 120Hz, or 144Hz.
Screen Burn-In Test & Fixer
Detect image retention and ghosting, then run the burn-in fixer to help clear it on OLED and LCD screens.
Touch Screen Test – Online Touchscreen Tester
Test your mobile smartphone or tablet screen for dead zones and multi-touch digitizer issues.
Phone Screen Test – Mobile Display Test
Run the full mobile display check: touch dead zones, dead pixels, backlight bleed, colour and burn-in.
What Is My Screen Resolution?
Instantly detect your exact logical and physical screen resolution, pixel ratio, and display dimensions.
iPhone Black Screen Test
Download a pure black image to test your iPhone for dead pixels, backlight bleed, and OLED defects.
How to Test a Monitor: The Full Sequence
Order matters. Physical defects come first, because no amount of calibration will fix a dead pixel and there is no point tuning colour on a panel you are about to return. Work down this list and you will have covered everything a professional review bench checks, minus the colorimeter.
- 1
Start with a white screen
A full white screen is the fastest first pass. It exposes dust and smudges on the glass, dead pixels as black dots, and any obvious yellow or blue cast in the panel's white point. Clean the screen now, before you start diagnosing — a fingerprint in the wrong place has fooled a lot of people into thinking they had a panel defect.
- 2
Cycle every solid colour for pixel faults
Run the dead pixel test through red, green, blue, black and white. A dead pixel stays black on all five; a stuck pixel keeps showing the same colour when the background changes. Note where any faults sit, because a pixel near the edge is far easier to live with than one in the centre. Stuck pixels are often recoverable with the pixel fixer.
- 3
Kill the lights and check for bleed
Turn the room lights off, let your eyes adjust for a couple of minutes, then run the backlight bleed test on a pure black field. Bright patches at the edges are backlight bleed; a soft corner wash that moves with your head is IPS glow and is normal. This is the single most useful test on a brand-new monitor, because significant bleed is a valid return reason within the first few weeks.
- 4
Set brightness, contrast and gamma
Now that you know the panel is physically sound, tune it. The monitor calibration tool walks through black level, white level, gamma and colour temperature in the order that matters — getting contrast right first stops every later adjustment from fighting you. Aim for gamma 2.2 and a 6500K white point unless you have a specific reason not to.
- 5
Verify colour reproduction
Once calibrated, confirm the result with the colour accuracy test. Look for smooth gradients without visible banding, distinct steps in the near-black and near-white ramps, and fully saturated primaries. If white still looks warm afterwards, the yellow tint fixer works through the software and hardware causes one at a time.
- 6
Confirm refresh rate, burn-in and resolution
Finish with the diagnostics that catch configuration mistakes rather than defects. The refresh rate test catches a 144Hz monitor left running at 60Hz, the screen resolution checker catches a display running below its native resolution, and the burn-in test matters on any OLED panel or any second-hand monitor that has spent years showing the same interface.
Testing a New Monitor vs Testing an Old One
A new monitor: test within the return window
You are looking for manufacturing defects while you can still do something about them. Test on day one, not after a month of use.
- •Dead and stuck pixels — most manufacturers only accept a return above a threshold, often three to five faults, so count and photograph them.
- •Backlight bleed and clouding — photograph in a dark room at your normal brightness, not at maximum, or support will dismiss the evidence.
- •Confirm the panel actually runs at its advertised resolution and refresh rate through the cable you were supplied with.
An old monitor: test for drift and wear
Panels age. You are looking for gradual changes rather than factory faults, and most of what you find can be improved rather than replaced.
- •A warm or dim picture is usually backlight ageing. Recalibrating the white point recovers a surprising amount of it.
- •Faint permanent shapes on a grey field are image retention or burn-in, most common on OLED panels and on any screen left on one static interface for years.
- •New dead pixels appearing over time are normal wear and are not repairable, but newly stuck pixels often respond to the pixel fixer.