About AspectFlip
A free, privacy-first video converter built for content creators.
What is AspectFlip?
AspectFlip is a free online tool that converts video between horizontal (16:9) and vertical (9:16) aspect ratios — entirely in your browser, with no file uploads and no watermarks. It was built to solve a common problem for content creators: you shoot or download a video in one format, but need it in another format for a different platform. Instead of wrestling with expensive desktop software or tools that upload your files to remote servers, AspectFlip lets you convert videos instantly in your browser.
Why We Built It
Most video conversion tools fall into one of two categories: they either require a desktop software download, or they are web-based tools that upload your video to a server — often to charge you for watermark removal or impose file size limits. We wanted to build something genuinely different. AspectFlip is built on the principle that a simple conversion tool should be fast, private, and free. By running FFmpeg entirely in the browser using WebAssembly, we eliminate the need for any server-side processing. Your files never leave your device.
Who Uses AspectFlip
- Social media creators who need to repurpose content across TikTok, YouTube Shorts, and Instagram Reels
- Marketers and agencies adapting video ads for different platform placements
- Students and professionals who need to resize video for presentations or websites
- Journalists and educators converting screen recordings or interview footage
- Anyone who wants fast, private, watermark-free video conversion without installing software
How It Works — Technical Details
AspectFlip is built with Next.js and uses FFmpeg compiled to WebAssembly (WASM) via the @ffmpeg/ffmpeg library. When you open the converter, the FFmpeg WASM binary is downloaded once to your browser. All subsequent video processing uses your device's own CPU — no internet connection is required after that initial load. The tool scales your video to fit the target aspect ratio and fills the remaining space with a clean black background, preserving all of your original content without any cropping. Output videos are encoded as MP4 with H.264 video and AAC audio for maximum compatibility across all platforms and devices.
Free and Ad-Supported
AspectFlip is free to use and will remain free. The site is supported by non-intrusive advertising through Google AdSense. We do not have premium tiers, credit systems, or feature paywalls. Every feature available on AspectFlip is available to every user, at no cost.