Check and Change Screen Size

With this extension, you can easily check and change your screen and window sizes. You can save your settings as presets.

It helps you quickly adjust and verify viewport sizes for responsive checks, QA workflows, and screenshot preparation. Key features: Always-on window size display on all websites One-click copy of width x height to clipboard Preset list with width, height, X, and Y position Edit mode to add, update, and delete presets Quick apply row for temporary size/position changes (without saving) Toggle visibility from the extension icon (with badge indicator when hidden) Supports both Japanese and English UI Great for: Front-end developers testing breakpoints QA teams validating fixed viewport scenarios Anyone needing fast, repeatable window size control