Convertior

Free Video Converter

Convert AVI to MP4

Convert AVI files to MP4 online. The tool runs in your browser for supported files and the guide below explains when this conversion is useful.

Convertior free online media converter logo

Free Online Media Converter

Convert images, audio, video and documents for free directly in your browser.

Your files stay on your device. No upload required.

Unit Converter

Convert to

Browser conversion works best with smaller files. Large video files may require a modern browser and may be slower on mobile.

Convert files online for free

Convertior is a free online media converter for images, audio, video and documents. You can convert common file types such as JPG, PNG, WEBP, MP3, WAV, MP4, MOV, PDF, TXT, Markdown, HTML and JSON.

Private browser-based conversion

Files are processed locally in your browser whenever possible, which means they do not need to be uploaded to a server. This makes conversion simple, private and fast for smaller files.

Supported file conversions

  • Image converter: JPG, JPEG, PNG, WEBP, AVIF, BMP, GIF, TIFF, ICO, TGA, PPM, PGM and PBM
  • Audio converter: MP3, WAV, OGG, M4A, AAC, FLAC and OPUS
  • Video converter: MP4, MOV, WEBM, AVI, MKV, MPEG and GIF
  • Document converter: PDF, TXT, HTML, Markdown and JSON

Free AVI to MP4 converter

AVI is an older video container that can hold many codecs and is not always convenient for web playback or mobile devices.

MP4 with H.264 video and AAC audio is one of the most compatible choices for websites, phones, messaging apps and presentations.

Best for

Modernizing older video files

Best for

Preparing clips for web upload

Best for

Making videos easier to play on phones and tablets

How to convert AVI to MP4

  1. Choose or drop your AVI file in the converter.
  2. Select MP4 as the output format.
  3. Adjust quality or bitrate settings if they appear for this file type.
  4. Click Convert Now and keep the tab open until the download is ready.

Quality and file-size notes

  • Keeping original quality uses slower encoding but reduces visible loss.
  • A fixed lower bitrate can shrink files but may soften details.
  • Source codec quality affects the final output.

Limitations before you convert

  • Very large video files are heavy for browser memory.
  • Unusual AVI codecs may fail if FFmpeg cannot decode them in the browser.

File privacy

For supported conversions, Convertior processes files inside your browser. That design avoids unnecessary file uploads and is one reason the tool may feel faster for small files. Conversion engines, fonts or libraries may still be downloaded by the page so the tool can run.

Frequently asked questions

Is this AVI to MP4 converter free?

Yes. The converter is free to use for common personal and everyday file conversion tasks.

Will conversion improve quality?

Changing format does not recreate missing detail. The best result comes from starting with the highest-quality original file you have.

Why did my conversion fail?

Failures usually happen because of unsupported codecs, damaged files, browser memory limits or very large files. Try a smaller file or a modern desktop browser.