Free Video Converter Online – MP4, AVI, MOV, MKV
Convert videos between formats online for free — MP4, AVI, MOV, MKV, WebM and more. No uploads, no registration, zero quality loss. Powered by FFmpeg WebAssembly: your video never leaves your device.
About This Tool
Learn what makes this tool special
What is a Video Converter?
A video converter is a tool that transforms video files from one format into another — for example MOV to MP4, AVI to WebM, or MKV to MP4. Converting video makes your files compatible with any device, platform, or application.
Why Use a Free Online Video Converter?
- Fix compatibility issues — AVI and MOV files often won't play on mobile devices; converting to MP4 solves this instantly
- Reduce file size — H.264 encoding shrinks video significantly without visible quality loss
- Social media ready — Instagram, YouTube, and TikTok all prefer MP4 format
- No software to install — Convert video online free from any browser, any device
- Complete privacy — Processing runs entirely in your browser; your video never leaves your device
Supported Video Formats
Convert between the most popular video formats:
- MP4 (H.264) — Universal: phones, web, and social media
- WebM (VP8) — Native web format, optimised for browsers and YouTube
- AVI — Windows and legacy application compatible
- MKV — Open container format with excellent quality retention
- MOV — Apple QuickTime and iPhone compatible
- GIF — Animated images from short video clips
How Video Conversion Works
Video conversion re-encodes your file using a different codec and container format. This tool uses FFmpeg — the industry-standard encoder — compiled to WebAssembly so it runs directly in your browser.
Your video is decoded from its source format, re-encoded using the selected codec (H.264 for MP4, VP8 for WebM, etc.), and packaged into the new container — all locally on your device. No server. No upload. Complete privacy.
Key Features
What makes this tool special
- Convert MP4, MOV, AVI, MKV, WebM, GIF and more — all major formats supported
- 100% browser-based using FFmpeg WebAssembly — no server, no upload, fully private
- No login required — convert video online free without registration
- Files never leave your device — complete privacy guaranteed
- Drag-and-drop upload with real-time progress bar and status messages
- All common input formats accepted: MP4, MOV, AVI, MKV, WebM, M4V, FLV, 3GP, WMV
- Convert to animated GIF — extract short clips as web-ready animations
- File size comparison shown after conversion (before vs after)
- Works offline after the FFmpeg engine is loaded once
- MP4 (H.264) default output — the universal format supported by every device
Quick Guide
Master this tool in seconds
- 1Click 'Choose File' or drag and drop your video onto the upload area
- 2Select your desired output format: MP4 (recommended), WebM, AVI, MKV, MOV, or GIF
- 3Click 'Convert' — FFmpeg will load (~30 MB) on first use and is cached for the session
- 4Watch the real-time progress bar as your video is re-encoded in your browser
- 5Click 'Download' to save the converted video to your device
Common Questions
Everything you need to know
Q.Is this video converter free?
Yes, completely free. There are no limits, no watermarks, no signup, and no hidden fees. You can convert as many videos as you need.
Q.Does converting video reduce quality?
Converting to MP4 (H.264) preserves excellent visual quality for most use cases. For lossless preservation, choose MKV with H.264. GIF output is scaled and limited to 10fps by design. Overall quality loss from format conversion is minimal when using modern codecs.
Q.Is my video uploaded to any server?
No. All conversion is performed locally in your browser using WebAssembly (FFmpeg.wasm). Your video file never leaves your device — not even a single byte is sent to any server.
Q.Why does it take a moment before converting starts?
On first use, the FFmpeg WebAssembly engine (~30 MB) needs to download. This is a one-time download per session. After that, it's cached in memory and conversions start instantly.
Q.What input video formats are supported?
You can upload MP4, MOV, AVI, MKV, WebM, M4V, FLV, 3GP, WMV, and most other common video formats. If your format isn't listed, try uploading it — FFmpeg supports hundreds of formats.
Q.What output formats can I convert to?
You can convert to MP4 (H.264 — recommended for universal compatibility), WebM (VP8 — optimised for web), AVI, MKV (H.264), MOV (QuickTime/Apple), and animated GIF.
Q.Is there a file size limit?
There is no hard limit, but files over 500 MB may be slow or fail depending on your device's available RAM. For best results, use files under 500 MB. Larger files work best on desktop computers with more memory.
Q.Which is the best output format?
MP4 (H.264) is the best choice for most users — it plays on every phone, computer, browser, and social media platform. Choose WebM for web embedding, MOV for Apple/iPhone, and MKV for archiving.
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