Debug viewport quickly
What Is My Viewport? Live Width & Height
See your browser viewport width and height instantly in CSS pixels — live innerWidth, innerHeight, visualViewport, and safe-area insets, plus a width simulator.
How to interpret these values
These readouts describe the browser layout area in CSS pixels, not your display hardware. For panel resolution and density, use the screen checker and PPI calculator.
Tip: rotate or pinch-zoom on mobile to see visualViewport updates in real time.
Viewport size vs screen resolution
Your screen has a fixed hardware resolution; your viewport is what CSS layouts use — the visible area of the page that changes with window size, zoom, and mobile browser chrome.
Screen resolution
Hardware pixels from your device panel.
Viewport size
CSS layout area after browser UI and zoom.
Need display resolution? Check the screen resolution checker or CSS viewport units (vh & dvh).
When you need this tool
Bug reports
Capture exact repro sizes like 390×844, DPR 3.
Layout checks
Validate breakpoints and 100vh behavior on mobile.
Safe area debugging
Read env() insets for notched and dynamic-island devices.
Viewport unit testing
Pair with dvh comparison to compare vh, svh, lvh, and dvh.
Tip: rotate your device to instantly verify portrait and landscape behavior.