Text Clarity Test (Blurry Text, Scaling & Subpixel Check)
Diagnose blurry, fuzzy or color-fringed text on your monitor. This test checks your OS display scaling, 1:1 physical pixel mapping, RGB 4:4:4 vs 4:2:0 chroma subsampling, and RGB/BGR/OLED subpixel rendering.
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Detected physical pixels
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OS / Browser scaling (DPR)
10px: The quick brown fox jumps over the lazy dog — 0123456789 Il1O0 ({[|]})
12px: The quick brown fox jumps over the lazy dog — 0123456789 Il1O0 ({[|]})
14px: The quick brown fox jumps over the lazy dog — 0123456789 Il1O0 ({[|]})
16px: The quick brown fox jumps over the lazy dog — 0123456789 Il1O0 ({[|]})
20px: Sphynx of black quartz, judge my vow — 1920×1080 2560×1440 3840×2160
Your Text Clarity Diagnosis
Evaluated
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What this text clarity test checks
Blurry or rainbow-fringed text on a desktop monitor almost always comes from one of four concrete causes rather than a "bad screen": (1) running below native resolution, (2) HDMI/DisplayPort YCbCr 4:2:0 or 4:2:2 chroma subsampling throwing away half of the color resolution, (3) non-standard subpixel layouts (such as BGR on certain VA/IPS panels or triangular/RWBG subpixels on QD-OLED and WOLED monitors) clashing with Windows ClearType, or (4) fractional OS scaling and monitor "Super Resolution" sharpness filters. The three test boxes above isolate each cause in seconds.
Before you start
Reset browser zoom to 100% (Ctrl+0 on Windows/Linux, Cmd+0 on macOS) so the 1:1 physical pixel canvas isn't resampled by the browser.
Check your monitor OSD "Sharpness" setting. Many monitors ship with Sharpness at 50 or 60. Raising it adds ugly white halos around letters; lowering it blurs every stroke.
How to run the test
Check the 1px physical lines and checkerboard (left & middle boxes): Every alternating white and black line should have identical thickness, and the 1px checkerboard should look like a flat, even grey rectangle. If you see thick-thin bands or moiré waves, your monitor is not running at its native resolution (or Overscan/Aspect scaling is enabled in the OSD).
Check the Chroma 4:4:4 box (right box): Read the blue text on the red bar and the magenta text on the blue bar. Under full RGB 4:4:4, every letter and digit is razor-sharp. Under YCbCr 4:2:0, the letters melt into unreadable blocks.
Inspect the 10px–20px type specimen in both Dark and Light polarity. Look closely at the tops of horizontal strokes (for pink/green QD-OLED fringing) and vertical stems (for BGR red/blue fringing).
Select the symptom you see in the dropdown to generate the exact fix for your OS and panel.
How to read your results (Subpixel layouts & Chroma 4:4:4)
RGB vs BGR vs QD-OLED subpixelsWhen subpixel geometry doesn't match what the OS font rasterizer expects, colored fringes appear on letter edges.RGB 4:4:4 vs YCbCr 4:2:0At 4:2:0, color information is quartered into 2×2 pixel blocks—fine for movies, terrible for colored IDE syntax and UI text.
Display Setup
Recommended OS Scaling
Best Text Fix
27" 1440p (109 PPI) IPS / VA
100% (Windows) · BetterDisplay HiDPI (macOS)
Run Windows ClearType tuner; on macOS enable HiDPI scaling so macOS doesn't use blurry low-DPI grayscale AA
27"–32" 4K (138–163 PPI)
150% (27") or 125–150% (32")
Set native 3840×2160 resolution + RGB 4:4:4 Full in GPU driver
1440p QD-OLED / WOLED
100%–125%
Use dark mode carefully, keep sitting distance ≥65 cm, or switch to 4K 27"/32" OLED (~140–166 PPI) where fringing is invisible
BGR-layout VA / 43" 4K monitor
100%–125%
Run `cttune.exe` in Windows and pick the BGR sample boxes on Step 2
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When results can be misleading
macOS on 1440p non-Retina external monitors: Since macOS Mojave removed subpixel antialiasing, macOS only renders truly crisp fonts at 2× Retina HiDPI scaling. A 27-inch 2560×1440 monitor at native 1× scaling looks noticeably softer on a MacBook than on a Windows PC next to it—using a tool like BetterDisplay to enable a HiDPI framebuffer fixes this.
Single blurry Windows desktop apps: If your browser passes all three checks above but one older installer or utility looks blurry at 125% or 150% scaling, right-click that app's `.exe` → Properties → Compatibility → Change high DPI settings → check Override high DPI scaling behavior (Application).
Text clarity test vs related tests
If your text is sharp here but dark greys look washed out or banded, run our monitor color test to verify Full 0–255 RGB range and gamma. If text smears or leaves a dark shadow while scrolling, check your pixel transition speed in the response time and ghosting test.
Frequently asked questions
Why does my 4K monitor have blurry text in Windows 11?
First check Settings → System → Display and confirm Display Resolution is set to 3840×2160 (not 1920×1080 or 2560×1440). Second, set Scale to 150% on a 27-inch 4K monitor or 125–150% on a 32-inch 4K monitor. Third, check our Chroma 4:4:4 box above: if you connected over an older HDMI port at 4K 60/120 Hz, the driver may have dropped to YCbCr 4:2:0.
Why does text on my OLED gaming monitor have pink and green fringes?
First- and second-generation QD-OLED panels arrange subpixels in a triangle (with green at the top and red/blue at the bottom), while WOLED panels include a fourth white subpixel (RWBG/RGWB). Windows ClearType is hardcoded for vertical RGB stripes, so high-contrast horizontal edges show a 1-pixel green fringe on top and magenta fringe on the bottom.
How do I know if my monitor uses a BGR subpixel layout?
Run the Windows ClearType Text Tuner (press Win+R, type cttune, press Enter). On the second screen of the wizard, Windows shows two large boxes—one rendered for RGB and one for BGR. If the right-hand BGR box looks dramatically sharper than the left-hand RGB box, your panel uses BGR subpixels.
Why does my 1440p monitor look blurry on my MacBook?
macOS disables subpixel font smoothing and treats 2560×1440 as a standard-DPI display (1× scaling), whereas it renders 4K and 5K displays using 2× Retina supersampling. Creating a scaled HiDPI resolution (such as 2560×1440 HiDPI rendered from a 5120×2880 framebuffer) restores sharp text on macOS.
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