AVI is one of the oldest video formats still floating around. It turns up on old hard drives, camcorder backups and family archives. Modern phones and TVs often refuse to open it, and many websites will not accept it as an upload.
This AVI to MP4 converter works in a browser tab like an online tool, but nothing is uploaded. AVI files take longer to convert than most videos, and they can be up to 2 GB, so it pays to know what to expect. Here is how to plan for the wait and get a clean MP4 from an old file.
How to convert AVI to MP4
- Drop your .avi file onto the tool above. Several files at once are fine.
- Make sure "Convert to" shows MP4.
- Choose a Quality. Balanced suits most old videos.
- Keep "Keep the sound" on so the sound comes with the picture.
- Press Convert. Wait for it to finish, then save the MP4 or take a zip.
That is all it takes to turn an AVI file to MP4. This free AVI to MP4 converter has no account, no watermark and no charge. Video tools do not count toward the free daily limit, which covers document conversions only.
Why AVI conversion takes longer
Newer formats convert quickly, because your browser can already read them. AVI is an old container whose picture can be one of many formats from the camcorder and early PC software era, and browsers cannot open it on their own. So AVI files take a slower route through the tool.
The work still happens inside the page, on your own computer. It takes longer, and it accepts AVI files up to 2 GB. The note beside the Convert button says "Slower for this file, on this device" so you know before you begin.
| Most files | AVI and similar files | |
|---|---|---|
| Which files | Files your browser can read | Formats such as AVI that it cannot |
| Speed | Quicker | Slower |
| Size limit | None | Up to 2 GB |
| Where it runs | Your device | Your device |
Tips for a smoother wait
- Close heavy tabs and apps so the converter has more of your computer to use.
- Keep this tab open and in front while it works.
- Cut out parts you do not need first with trim video.
- Convert big batches one after another rather than all in a rush.
What you get from an old AVI
The result is an MP4 with H.264 video and AAC sound, which plays on almost any phone, TV, editor or website. You also get a file that is easier to organise, search and back up, because modern photo and video libraries understand it without any help.
Can you go from AVI to MP4 without losing quality? Most AVI files hold an older picture format, so the picture is re-encoded once into H.264 and the Quality setting matters. Balanced stays visually close to the source, Smaller makes a lighter file and Best keeps the most detail. Some newer AVI files already hold H.264, and then the picture is copied across as it is.
Old AVI files are often low resolution, such as clips from early digital cameras. Converting cannot add detail that was never there, so a small, soft video stays small and soft. What you gain is compatibility, and often a smaller file.
Some AVI files use a picture format that is rare or damaged. If a file will not convert, try another copy of it, or a different tool to repair it first.
Convert AVI to MP4 on Windows or Mac, privately
Open this page in current Chrome, Edge or Firefox on a Windows PC or a Mac. There is nothing to install. The first AVI you open may take a moment longer to start than the ones after it.
AVI files are often personal: weddings, birthdays, holidays. Because the whole conversion happens on your own computer, none of it is sent to a server. That also means you do not have to wait for an upload before the work starts, which for a large AVI can save a good deal of time on a slow connection, and there is nothing to delete from another system afterwards. Read more on the privacy page.
- The server does no video work.
- The result is yours to keep, with no watermark.
- To make the MP4 smaller still, use compress video.
AVI is not the only older format that takes longer, and the page for WMV to MP4 covers its Windows cousin. Have a mix of formats? The main convert video page handles them all.
When an AVI is worth converting
AVI dates from the 1990s, when video on a PC was a new idea. Cameras, capture cards and early editing programs saved to it, and a lot of those files have survived on old disks and discs. The format itself is just a container, so what is inside can vary a great deal from one file to the next.
That variety is the real reason AVI files are a hassle today. One may play perfectly on your computer while another from the same year shows a black picture or no sound. Moving everything into MP4 gives you one predictable format for the whole collection.
- Digitising a pile of old camcorder backups into one tidy folder of MP4 files.
- Making an old clip small enough to send in a message.
- Getting a file to play on a smart TV, which usually dislikes AVI.
- Preparing footage for an editor that no longer opens the old format.
Size and speed expectations
An AVI is converted at a slower pace, so a long file near the 2 GB limit can take a while. The Quality options show an estimated size before you start, which helps you plan. If you only need a short part, trim first and convert the shorter piece. The same goes for clips with a long dead stretch at the start or end, which only add waiting time and make the finished file larger than it needs to be.
If your AVI is small and the result still feels slow, nothing is wrong. It is the price of the converter running entirely on your own machine, with nothing sent away.
After the conversion
Open the MP4, skim through it and check the sound. If the clip came from a camera held at an odd angle, rotate video can straighten it. If you want it lighter for sharing, use compress video as a second pass.
Rescue your old AVI files
To convert AVI to MP4, drop the file into the tool above and press Convert. Be patient while it works, and you will end up with a file that plays nearly everywhere. Your old AVI stays untouched on its disk, so there is no risk in trying. Convert one file first to see how long it takes, then queue up the rest once you know what to expect. A tidy folder of MP4 files is a much better home for family footage than a pile of formats that nobody can open.
It is free, private and free of watermarks, so start to convert AVI to MP4 above.
