Viewport Resizer

Resize your browser's inner viewport to an exact pixel size — perfect for testing responsive designs, capturing screenshots at a specific resolution, or matching a video/social media aspect ratio before recording your screen. Why it's useful Testing a website at "1920×1080" isn't the same as your window actually measuring 1920×1080 inside - browser chrome (toolbars, borders) eats into that space. Viewport Resizer calculates the difference and resizes the outer window so your inner content area lands on the exact dimensions you need. Features -One-click presets grouped into categories: Video Resolutions (4K, 1440p, 1080p, 720p, 480p, vertical), Devices (common phone/tablet/desktop breakpoints), and Social Media (post and story dimensions for major platforms) -Custom size input for any exact width × height -A companion "Ruler & Resize" page with a live pixel ruler, on-screen readout of your current inner size, and the same presets — great for visually checking size while you work -Clean, minimal dark-mode interface -No data collection, no tracking, no account required Permissions Viewport Resizer only requests the minimum needed to resize the active tab's window — nothing else. It doesn't read your browsing history, page content, or any personal data. Built for developers, designers, and anyone who needs a precise, reliable inner-viewport size without guesswork.