AVI to MP4
Convert old AVI video to MP4.
- Free
- No signup
- Nothing uploaded
- No watermark
Drop a file here
AVI files · read on your device, never uploaded
Made on your own device. The video is never uploaded.
How to Convert AVI to MP4 Online
AVI is a 1990s container that can hold almost any codec, which is why one AVI plays and the next does not. This turns it into H.264 MP4, the combination that plays everywhere. Browsers cannot decode AVI natively, so the full converter is loaded into the page and does the work on your machine. Any sound track comes along with the picture.
Converts old AVI video to MP4. AVI is a container from the 1990s that can hold almost any codec, which is why one AVI plays and another does not — converting to MP4 with H.264 removes that uncertainty.
No software to install Free Works on any device
Step-by-Step Guide to Convert AVI to MP4
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1. Drop your MP4, AVI, MKV file in, or click to choose one
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2. Set the options if the defaults do not suit you
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3. Press the button — AVI to MP4 runs in your browser and the result downloads straight to your device
What is AVI to MP4 Conversion?
Converts old AVI video to MP4. AVI is a container from the 1990s that can hold almost any codec, which is why one AVI plays and another does not — converting to MP4 with H.264 removes that uncertainty.
MP4 files
.MP4 .AVI .MKVConvert old AVI video to MP4.
At a glance
- Takes: .avi (MP4, MKV, WebM and MOV are also accepted)
- Gives: An .mp4 with H.264 video
- Engine: The full converter in your browser, since no browser decoder exists for AVI
- Audio: Carried across with the video
- Runs: On your machine, so a long file takes as long as your computer needs
- Price: Free, no signup, no watermark
Why Use Video Tools in Your Browser?
Phone videos are large, and every app has its own rules for length, shape and format. Trimming, compressing, converting and resizing clips here gets them ready to post or send without uploading your footage to a stranger’s server.
“A shorter, smaller clip is far more likely to get watched.”
- Clips that fit upload limits
- GIFs from short moments
- Subtitles converted and shifted
- Screen recordings without software
- Vertical videos for Reels
- Sound pulled out as MP3
- Only the scenes you want
- Footage kept on your device
Popular Uses for Video Converters
These are the video jobs people come back for again and again.
- Reels and Shorts Crop a landscape clip into a vertical video for Instagram Reels or YouTube Shorts.
- WhatsApp status Cut a long video into short parts that fit a WhatsApp status.
- Email and chat limits Compress an MP4 so it can be sent without a file-too-large error.
- Reaction GIFs Turn a funny moment from a clip into a GIF to share in chats.
- Audio from video Save the soundtrack or speech from a video as an MP3 file.
- Tutorial recordings Record your screen to show a colleague how to do a task.
- Subtitle fixes Convert SRT to VTT or shift subtitle timing when words arrive too early.
- Playback problems Convert MOV, MKV or AVI files to MP4 so they play on any phone or TV.
What the AVI to MP4 Converter Does
Accepts MP4, AVI, MKV, WEBM, MOV
Understands MP4 structure rather than treating the file as bytes
Says plainly where the result approximates rather than reproduces
Uses WebCodecs and your machine’s own hardware encoder rather than a software fallback
Copies the audio track untouched where the target container accepts it, which is faster and lossless
Why Use ToolXkit for AVI to MP4?
Your files stay with you
Everything runs inside your browser. Nothing you open or type is uploaded to a server.
Free, with no catch
No signup, no watermark and no daily limit on how often you use it.
Fast
Results appear in seconds, because nothing has to travel over the internet and back.
Works on any device
Use it on a computer, tablet or phone, in Chrome, Edge, Firefox or Safari.
Nothing to install
No app, no extension and no desktop program. Open the page and start.
Made for real people
Plain words and clear buttons, built by one developer who wanted tools like this to exist.
Clip Tools for Different Users
Content creators
Trim, crop and resize clips for each platform without a desktop editor.
Teachers and trainers
Record lessons on screen and cut videos down to the useful part.
Small businesses
Make short product videos and GIFs for shop pages and status updates.
Students
Shrink project videos to meet the upload limit of a college portal.
Support teams
Record bugs and walkthroughs, then compress them for tickets and emails.
Families
Share wedding and birthday clips that open on everyone’s phone.
Best Times to Trim or Compress a Video
Video tools are most useful when you are:
- Posting a Reel or Short
- Sending a clip over email
- Playing a file your TV rejects
- Making a GIF for a chat
- Recording a how-to for a colleague
- Adding subtitles to a lesson
- Saving only the best moments
- Pulling music out of a clip
Tips and Good to Know
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An AVI holding a codec the converter does not know fails with a message, not a broken file. Try a desktop player's export in that case.
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Everything is re-encoded, so quality is approximate rather than identical. Keep the original if it is the only copy.
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For a file that is already MP4 and only too big, use Compress MP4 instead of converting.
Frequently Asked Questions
Answers to common questions about this tool.
Do I need to install anything to convert AVI to MP4?
No. AVI to MP4 runs entirely in your browser — there is nothing to download, no extension and no desktop program. It works the same on Windows, macOS, Linux, Android and iPhone.
Is it safe to convert AVI to MP4 online?
Safer than the usual alternative, yes. Most online tools upload your file to a server you know nothing about, where it sits until someone deletes it. Here the file never leaves your device — the processing happens in the page itself, so there is no server copy to leak, retain or sell.
Is there a limit on video length or size?
The site sets no limit. Video processing happens on your own device, so long or high-resolution clips need more memory and time. Short phone clips are quick, while hour-long 4K files are better handled on a computer.
Why is AVI to MP4 slower than a desktop editor?
Video work is heavy, and here it runs inside a browser tab using your device’s own processor. That keeps the footage private, but it can take longer than installed software. Keep the tab open until it finishes.
Will the quality drop after compression?
Some detail is lost when a video is made much smaller. Moderate compression is hard to notice on a phone screen, while very small targets make fast motion look blocky. Try a setting and watch the result before sharing.
Can I turn a landscape clip into a vertical Reel?
Yes. Reels & Shorts Maker and Resize & Crop Video crop a wide clip to the tall 9:16 shape that Reels, Shorts and status updates use. Download the vertical version and it is ready to post.
Further reading
- Web video codec guide (MDN) How video codecs like H.264, VP9 and AV1 work and which browsers support them.
- Video file format (Wikipedia) Why MP4, MKV, MOV and WebM are containers, and what that means for playback.
- Subtitles (Wikipedia) How subtitles are timed and stored, including the SRT and WebVTT formats.
More Video Tools
Other free tools for the same kind of job.
- Compress Video Shrink a clip to get it under a size limit. Open tool
- Trim Video Cut a clip with handles you drag and a timecode you can type. Open tool
- Video Converter Convert between MP4, WebM and MOV. Open tool
- Video to MP3 Pull the soundtrack out of a video file. Open tool
- Change Video Speed Make a clip slow motion, or speed it up. Open tool
- Compress AVI Shrink AVI video files. Open tool
- Compress MKV Shrink MKV video files. Open tool
- Compress MOV Shrink a QuickTime .mov video. Open tool
- Compress MP4 Shrink an MP4 video in your browser. Open tool