When something looks too big, too small or cut off on a screen, the first question is always: what resolution is this? This checker answers it live. It reads the display properties your browser reports — total screen size, the area actually available, the current window and viewport sizes, device pixel ratio, orientation and colour depth — and updates them the moment you resize the window or rotate the device, so you can watch the numbers change.
The Numbers, Explained
Screen size is the full pixel dimensions of the display. Available area subtracts things like the taskbar or dock. The window size includes browser chrome, while the viewport is the part web pages actually render into — the figure designers and developers really need. Device pixel ratio explains why a phone reporting 390 by 844 CSS pixels can still have a much sharper physical screen: a ratio of 3 means nine physical pixels behind every CSS pixel. Colour depth reports how many bits describe each pixel's colour.
How to Check Your Resolution
- Open this page on the device you want to measure.
- Read the live figures for screen, window and viewport.
- Resize the browser or rotate the device to see values update.
- Copy the full report if you need to share it with support.
Who Uses These Figures
Developers reproduce layout bugs that only appear at a specific viewport. Support staff ask users for their resolution before diagnosing display problems. Designers verify breakpoints and check how a site behaves between phone, tablet and monitor sizes. Anyone buying a monitor or comparing devices can confirm what they actually have.
Frequently Asked Questions
Why is my viewport smaller than my screen?
Browser toolbars, scrollbars and the operating system's own bars all take space. The viewport is what remains for the page itself.
My phone shows fewer pixels than its specification. Why?
Phones report CSS pixels, not physical ones. Multiply by the device pixel ratio shown here to get the true panel resolution.
Does this work on any device?
Yes — any device with a web browser, including TVs and game consoles, can report these figures.