How to Convert MOV, MKV or AVI Video to MP4
You download a video, double-click it, and nothing happens. Or your phone says the format is not supported. This usually means the file is in a format your device does not like, such as MOV, MKV or AVI. The fix is simple: convert it to MP4.
Why MP4?
MP4 is the format almost everything understands. Phones, laptops, smart TVs, WhatsApp, YouTube and most editing apps all accept it. If you are not sure which format to choose, choose MP4.
What the other formats are for
- MOV comes from Apple devices and QuickTime. It is fine on a Mac, but some Windows apps struggle with it.
- MKV is popular for movies and downloads because it can hold many audio and subtitle tracks.
- AVI is an old format. Some older TVs and car players still need it.
- WebM is made for websites.
How to convert, step by step
- Open the Video Converter.
- Choose your file, or drag it onto the box.
- Pick MP4 under "Convert to".
- Leave quality on Balanced. Choose Smaller file if you want to send it by email or chat.
- Press Convert video and wait for the bar to finish, then download.
Making the file smaller
Big videos are often bigger than they need to be. If you pick 720p instead of keeping the original size, the file can shrink a lot, and on a phone screen you will hardly see the difference. Try 480p for a quick message or 1080p when you care about sharpness.
A few honest warnings
The conversion happens inside your browser, so it uses your own computer. That is great for privacy because your video is never uploaded. It also means a long 4K video can be slow and may use a lot of memory. For short clips from a phone, it works well. For a full movie, a desktop program like HandBrake is a better choice.
Also, the first time you convert, the page downloads the conversion engine, about 30 MB. After that it is saved by your browser and starts faster.
Need only the sound?
Choose MP3 instead of MP4 and you get just the audio. This is handy for lectures, interviews and voice notes recorded as video.
Frequently asked questions
Will converting to MP4 reduce quality?
Converting re-encodes the video, which can lose a little detail. At the default quality the change is hard to see. Choosing a lower resolution, such as 720p, makes the file much smaller with a small loss of sharpness.
How long does conversion take?
It runs on your own device, so it depends on its speed and the length of the video. A short phone clip may take under a minute, while a long HD video can take many minutes. Keep the tab open while it works.
Why does the first conversion take longer?
The converter downloads its video engine, about 30 MB, the first time you use it. After that the browser keeps it, so later conversions start quickly.
Is there a size limit?
Files up to 1 GB each can be added. Very large files may fail on devices with little memory. If that happens, choose 720p or 480p, or split the video into shorter parts.
Open the free Video Converter. It runs in your browser, so nothing is uploaded.