Screen Resolution & Size Checker
Check your screen resolution, viewport size, DPR, aspect ratio, and more. Use built-in test patterns to check sharpness, scaling, and display quality.
Display information
Test patterns
Set OS scaling and browser zoom to 100% for the sharpest grid and ruler results. Physical pixel counts use CSS pixels × DPR.
How to read these numbers
Screen vs viewport
Screen resolution is what the OS reports for the display. Viewport is the browser content area and is usually smaller because of toolbars and window chrome.
Device pixel ratio
A DPR above 1 means multiple physical pixels are used for each CSS pixel, which is common on HiDPI and Retina displays.
Test patterns
Use the 1px grid and checkerboard to spot blurry scaling. The ruler can be compared with a physical ruler after you enter the correct diagonal for PPI.
Frequently Asked Questions
Why do lines look blurry?
Non-native OS scaling or browser zoom often softens 1px lines. Try 100% scaling and zoom, then re-check the grid.
Is PPI exact?
PPI is calculated from reported screen pixels and the diagonal you enter. Measure the panel diagonal with a tape for best accuracy.
Does this upload anything?
No. Everything runs locally in your browser.
What is my screen resolution?
Your screen resolution is shown at the top of the tool under “Screen.” It represents the display dimensions reported by your operating system, such as 1920 × 1080.
What is the difference between screen resolution and physical pixels?
Screen resolution is typically reported in CSS or logical pixels, while physical pixels represent the actual number of hardware pixels on the display. On high-DPI screens, one CSS pixel may use multiple physical pixels.