MP4 is the gold standard for video — compatible with every device, browser, and platform. Convert AVI, MKV, MOV, WebM, WMV, FLV and dozens more formats to MP4 in seconds.
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Up to 100 MB free • Outputs: MP4
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Convert your files in three simple steps — no software, no signup.
Upload any video file — AVI, MKV, MOV, WebM, WMV, FLV, TS, MTS, or any other format. Maximum file size is 500 MB.
Choose your codec (H.264 for compatibility or H.265 for better compression) and quality preset. Original resolution is maintained by default.
Download your universally compatible MP4 file, ready to share on any platform, play on any device, or upload to any video hosting service.
MP4 is supported by every major operating system, browser, social media platform, streaming service, and consumer device on the market.
MP4 with H.264 is the native video format for iPhone, Android, and all mobile devices — ensuring smooth playback without transcoding.
YouTube, Instagram, TikTok, Twitter, and Facebook all recommend MP4 as the preferred upload format for best quality and compatibility.
MP4 handles everything from 480p to 4K Ultra HD. H.265/HEVC delivers 4K video at half the file size of H.264 without quality loss.
Audio is automatically encoded to AAC — the most compatible audio format for MP4 — preserving all original audio channels.
Video files are processed in an isolated environment and deleted from our servers within one hour of conversion.
All the formats you need, all in one place.
| Format | Description | Extension | Best Used For |
|---|---|---|---|
| AVI → MP4 | Convert legacy AVI to modern MP4 | .avi |
Old camcorder footage, DVD rips |
| MKV → MP4 | Matroska to universally compatible MP4 | .mkv |
Streaming-ready output, device compatibility |
| MOV → MP4 | Apple QuickTime to cross-platform MP4 | .mov |
Sharing Mac/iPhone video on Windows/Android |
| WEBM → MP4 | Web-optimised WebM to portable MP4 | .webm |
Downloading web videos for offline use |
| WMV → MP4 | Windows Media Video to MP4 | .wmv |
Playing old Windows video on Mac or iPhone |
| FLV → MP4 | Flash video to modern MP4 | .flv |
Archiving old Flash-era video content |
| TS → MP4 | MPEG Transport Stream to MP4 | .ts |
DVB recordings, broadcast video files |
From everyday users to professionals — see how people rely on this tool every day.
Convert any format to MP4/H.264 — YouTube's recommended upload codec for fastest processing and best quality retention.
Both platforms accept and prefer MP4. Convert Reels, Stories, and short clips to MP4 for smooth, error-free uploads.
MP4 with H.264 is the native format for all mobile devices. Convert MKV or MOV files to MP4 for direct playback without apps.
Convert MOV, MKV, or AVI to MP4 so files play natively in Windows Photos, Movies & TV, and Edge browser without codecs.
Deliver edited footage to clients as MP4 — it opens immediately on any computer without confusion about codecs or players.
MP4 files attach to emails and upload to Google Drive, Dropbox, and iCloud without compatibility warnings on the recipient's end.
See how we compare to desktop software and other online converters.
| Feature |
Our Tool TransmuteBox |
HandBrake | Other Online |
|---|---|---|---|
| Stream copy (zero re-encode) | |||
| H.264 & H.265 output | |||
| AAC audio auto-encoding | H.264 only | ||
| Resolution selector | |||
| No file size limit per format | |||
| Drag-and-drop upload | |||
| No watermark on output | Sometimes |
Built on industry-standard open-source tools for maximum quality and reliability.
MP4 (MPEG-4 Part 14) has become the universal currency of digital video. Whether you're uploading to YouTube, sharing on WhatsApp, or playing back on a smart TV, MP4 is the format that just works. Here's everything you need to know about converting to MP4 and getting the best results.
MP4's universal dominance comes from its adoption as the default format by Apple (iPhone), Google (Android), YouTube, and every major social media platform simultaneously. By 2010 it had already displaced older formats like AVI and WMV for most consumer uses.
The key reasons for its ubiquity: it stores H.264 video efficiently, uses AAC audio (equally universal), and the container spec is an open ISO standard — so any manufacturer can implement support for free.
Many MKV files found in media libraries already contain H.264 or H.265 video with AAC audio — exactly what MP4 needs. In these cases, converting MKV to MP4 is a remux: the video and audio data are copied byte-for-byte into the new container without any re-encoding. This is lossless and completes in seconds.
Re-encoding only occurs when the MKV uses a codec not supported inside MP4 (such as DTS audio), requiring those streams to be transcoded.
MP4's companion audio codec is AAC (Advanced Audio Coding). It replaced MP3 as the default because it delivers better quality at smaller file sizes. All modern phones, browsers, and media players support AAC natively. When TransmuteBox converts audio to AAC for MP4 output, it targets 192 kbps — a quality level indistinguishable from the original for most content.
Different platforms have different sweet spots for MP4 uploads: