Convert MKV to MP4 free: no sign-up, no upload
Convert MKV to MP4 free. There is no sign-up or login, no watermark, and nothing is uploaded, because your files never leave your browser. It turns a Matroska MKV video into an MP4 that plays on phones, TVs and in apps that refuse MKV.
MKV is popular for downloaded and ripped video, screen captures from some recorders and files with several audio or subtitle tracks. Many phones, smart TVs, game consoles and editing apps cannot open it, which is why an MP4 copy is useful.
MKV is a flexible container that can hold many kinds of video, so the work involved depends on what is inside. This pair may need a one-time engine download before the first conversion, depending on your browser. MKV files tend to be large and conversion is slow for long videos, so give it time and do not close the tab.
- Free
- No sign-up
- Never uploaded
- No watermark
Your files are converted on your device and never uploaded.
How to convert
- Drag your MKV files onto the page, or choose them with the file picker.
- Pick MP4 as the target format.
- Review the video options shown for MP4 before converting.
- Press Convert and wait for each file to finish.
- Download a single MP4 file, or take several results together as one ZIP.
Features
- Converts Matroska MKV video to MP4
- Helps files play on phones, TVs and consoles
- Keeps picture and sound together
- Batch convert several videos
- Download one file or a ZIP of all results
- No watermark, no sign-up, no upload
- May use a one-time engine download, depending on your browser
Supported formats
About the formats
About MKV
MKV, or Matroska, is an open container that can hold almost any video and audio codec together with many audio tracks and subtitles. That flexibility is also why player support varies so much.
About MP4
MP4 is the most widely supported video container. With H.264 video and AAC audio it opens on nearly every phone, TV and editor.
What may not carry over
An MP4 normally holds one video track and one audio track here. Extra audio languages and embedded subtitle tracks that an MKV may contain should not be assumed to be kept. If you need them, keep the MKV as well.
Privacy: how it works
- Your videos stay on your device. The page reads each file with the browser's file API, converts it with code running in the tab, and hands the result back as a download. No upload happens, so there is no copy of your file on our servers to protect, delete or leak.
- There is nothing to sign up for and no login. The converter does not ask for an email address, and it does not need to know who you are to do its job.
- Some conversions use a WebAssembly engine that your browser downloads once, the first time you need it. Only the engine is fetched, never your file, and the page shows the approximate size before it starts. Your browser caches it, so later conversions skip the download.
- You can check the claim yourself: open your browser developer tools, watch the Network tab while a file converts, and you will see no request that carries your file.
- MKV files are often large personal recordings. They are not copied anywhere during conversion. Depending on your browser, this pair may need a one-time engine download (about 31 MB) before the first conversion. The engine is cached by your browser, and your file is never part of that download.
Tips
- Keep the original MKV if it has several audio languages or subtitles you still want.
- Test with a short file before starting a long movie-length conversion.
- A large MKV can exhaust the memory of a phone, so use a computer for big files.
- Close other tabs and do not let the computer sleep during a long conversion.
- If the result will not play, try another player to rule out a player problem.
- Make sure you have the right to convert the video.
Frequently asked questions
Is it really free?
Yes. There is no price, no trial, no credit card and no watermark added to your results. Ulkaa Tool does the conversion with your own device, so there is no server bill to pass on to you.
Are my files uploaded?
No. Your videos are read and converted inside your browser and are never sent to Ulkaa or to anyone else. The result is created on your device and you save it from there. Some conversions load a small conversion engine the first time you use them. That download is the only network traffic, it contains no file of yours, and your browser keeps it for next time.
Do I need an account?
No. There is no sign-up and no login. Open the page, add your files and convert. An Ulkaa account is not needed for anything on this tool.
Is there a file size limit?
No limit is set by us. The real limit is your device: the conversion uses your own memory and processor, so very large files can be slow or fail on a weak phone or an older computer. Close other heavy tabs and convert videos one at a time if a big batch struggles.