Screen Sizer

Resize your browser window to mimic different screen sizes. Save, manage and share presets with your team.

Screen Sizer helps developers and QA engineers resize the browser window to mimic real device sizes and CSS breakpoints—no dev tools required. • Built-in presets — iPhones, iPads, Pixels, Galaxy devices, laptops, desktops, and standard breakpoints • Custom presets — save your own widths and heights with a name • Favorites — star presets for one-click access • Quick resize — type any width × height and apply instantly • Import/Export — share preset JSON files with your team so everyone tests the same sizes • Current size — see the window dimensions at a glance • Dark/Light theme — follows your system or choose manually Works in Chrome, Edge, and Firefox. All data stays in your browser; nothing is sent to any server.