What you can test with free tools
You might think you need expensive measuring equipment to evaluate a monitor. For professional-grade measurements, that is true. But for practical evaluation of everything from dead pixels to color accuracy to response time, free browser-based tools cover the vast majority of what matters.
The essential tests
Dead pixels: Display solid colors (white, black, red, green, blue) fullscreen and examine every area of the screen. Our Dead Pixel Test makes this process quick and simple.
Backlight bleed: Display a black screen in a dark room. Look for light leaking from the edges or corners. Mild bleed is normal on LCD panels. Severe bleed is a manufacturing defect.
Color accuracy: Display known reference colors and compare them visually to reference images on a calibrated device. Our Color Accuracy tool displays standard color patches. While this is not as precise as a colorimeter, it catches major issues.
Response time and ghosting: Use our Motion Test to display moving objects and observe trailing or smearing. Good monitors show minimal trails. Severe ghosting looks like a shadow following moving objects.
Refresh rate: Verify your monitor actually runs at its advertised refresh rate using our Refresh Rate Test. Many monitors need manual configuration to enable higher refresh rates.
Uniformity: Display 50% gray fullscreen and look for areas that are brighter or darker than the rest. Uniformity issues are common in larger displays and cannot be fixed through settings.
When to use professional equipment
If you do color-critical work like printing, fashion, or medical imaging, a hardware colorimeter is essential for accurate calibration. For gaming, general use, and most creative work, free browser-based tests provide more than enough information to evaluate a display.