Free Video Converter: No Sign-up, and Your Videos Are Never Uploaded
This video converter is free, needs no sign-up or login, and never uploads your videos. The file is read and re-encoded by your own browser, so it never leaves your device, and no watermark is stamped on the result. Add a clip from your phone, a screen recording or a downloaded film, choose the format you need and save it.
You can write MP4, WebM, MOV, MKV, AVI, WMV, FLV, 3GP, OGV, MPEG and MPEG-TS files, make a GIF or an animated WebP from a clip, or pull out the audio as MP3, M4A, WAV, FLAC and other formats. Older or specialised files such as VOB from a DVD, F4V, M4V and ASF can be opened and converted to MP4.
Video is heavy work, and your device does all of it. Some conversions use the video codecs your browser already has, while others load a conversion engine of about 31 MB the first time. Expect longer files to take a while, and keep the tab open until the download appears.
- Free
- No sign-up
- Never uploaded
- No watermark
Your files are converted on your device and never uploaded.
How to convert
- Drag your video files onto the page, or choose them with the file picker.
- Pick the target format, such as MP4 for phones and TVs or WebM for websites.
- Choose the settings offered for that format, for example whether you want a GIF or just the audio.
- Press Convert and keep the tab open while your device encodes the video.
- Download the finished video, or download several results together as a ZIP.
- Play the result from start to end before you remove the original.
Features
- Creates MP4, WebM, MOV, MKV, AVI, WMV, FLV, 3GP, OGV, MPEG and MPEG-TS.
- Opens VOB, F4V, M4V and ASF files and converts them to common formats.
- Makes a GIF or an animated WebP from a video clip.
- Extracts the audio track as MP3, M4A, WAV, FLAC, Opus and more.
- Converts several videos in a row and can package them in a ZIP.
- Uses the codecs built into your browser where it can.
- Loads a one-time engine of about 31 MB only for pairs that need it.
- Adds no watermark and no intro or outro.
Supported formats
| Format | Read | Write | Notes |
|---|---|---|---|
| GIF.gif | Yes | Yes | Limited to 256 colours per frame, with single-bit transparency. |
| MP4.mp4 | Yes | Yes | The most widely supported video format: plays on phones, browsers, TVs and editors. |
| WebM.webm | Yes | Yes | Open, royalty-free format from Google, usually VP9 or AV1 video with Opus audio. |
| MOV.mov | Yes | Yes | Apple’s QuickTime container, the default for iPhone and Mac screen recordings. |
| MKV.mkv | Yes | Yes | Matroska: an open container that holds any number of video, audio and subtitle tracks. |
| AVI.avi | Yes | Yes | Audio Video Interleave: a container Microsoft introduced in 1992. |
| WMV.wmv | Yes | Yes | Windows Media Video, Microsoft’s format from the early 2000s. |
| FLV.flv | Yes | Yes | Flash Video, the standard for web video in the Adobe Flash era. |
| F4V.f4v | Yes | No | F4V is an obsolete Flash format that is read only here; convert it to MP4. |
| 3GP.3gp | Yes | Yes | Small-file video container defined by 3GPP for early mobile phones. |
| OGV.ogv | Yes | Yes | Ogg video, usually Theora video with Vorbis audio. |
| MPEG.mpeg | Yes | Yes | MPEG-1 or MPEG-2 program stream, the format behind Video CDs and DVDs. |
| MPEG-TS.ts | Yes | Yes | MPEG transport stream, used in broadcast TV, Blu-ray and HLS streaming. |
| VOB.vob | Yes | No | VOB files come from DVD discs and are read only; convert them to MP4. |
| M4V.m4v | Yes | No | M4V is an MP4 variant; convert it to MP4, which every device plays. |
| ASF.asf | Yes | No | ASF is read only here; WMV is the video format that can be created. |
About the formats
Containers and codecs
A video file is a container holding separate video and audio streams. MP4, MOV, MKV, AVI and WebM are containers, and the codec inside decides quality and compatibility. MP4 usually holds H.264 video with AAC audio and plays on phones, browsers, TVs and editors, which makes it the safe default. MOV is the Apple QuickTime container and is the default for iPhone and Mac screen recordings.
WebM and MKV
WebM is an open, royalty-free format from Google, usually VP9 or AV1 video with Opus audio, and it plays in all major browsers. It can carry an alpha channel with VP9. MKV is Matroska, an open container that can hold many video, audio and subtitle tracks. It is common for downloaded films, but many TVs and phones cannot play it directly, so convert it to MP4 for those.
AVI, WMV, FLV and other legacy formats
AVI is a Microsoft container from 1992 and its files are larger than modern MP4. WMV is a Microsoft format from the early 2000s and works poorly on phones. FLV was the Flash era web video format and is obsolete now. 3GP is a small, low-resolution format made for early mobile phones, and OGV is Ogg video with Theora, which is rarely used today. MPEG and MPEG-TS come from DVDs, Blu-ray and broadcast TV.
F4V, M4V, VOB and ASF can be read but not written. F4V and M4V are MP4-style files, VOB comes from DVD discs, and ASF is the container behind WMV. Converting any of them to MP4 is the usual goal.
GIF and animated WebP
A clip can become a GIF, which is limited to 256 colours per frame and has no sound, so keep it short. An animated WebP is also made without sound and is usually smaller than a GIF at similar quality, but fewer old apps can show it.
Extracting audio
To keep only the sound, convert the video to an audio format. MP3 and M4A are small and play everywhere, while WAV and FLAC are lossless. The picture is dropped, so the result is a plain audio file.
Which engine runs
MP4, MOV, MKV and WebM conversions can use the video encoders built into your browser when it has them. AVI, WMV, FLV, 3GP, OGV, MPEG, MPEG-TS, GIF, animated WebP and the older read-only formats use a WebAssembly engine of about 31 MB, downloaded once and cached by your browser. The engine is the only thing fetched, never your video.
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.
- Screen recordings, family clips and work videos are often private. No frame of your video is sent to a server, so there is no cloud copy to worry about. Be aware that the file is processed in your device memory, so a very large video may not fit on a weak phone.
Tips
- For sharing, MP4 is the format least likely to cause a playback problem on the device of whoever receives it.
- For a website, WebM is a good fit and plays in every major browser.
- Convert MKV to MP4 if a TV, phone or editing tool will not open it.
- For a GIF, trim the clip to a few seconds first, because GIF files get big quickly and are limited to 256 colours.
- Lossy conversion discards detail, so always convert from the original recording, not from an already converted copy.
- Close other heavy tabs and apps before converting a long video, since your device does all the work.
- On a phone, plug in the charger for long jobs, because encoding uses a lot of processor power.
- Videos from DVDs or purchased downloads may be copy protected, and protected files cannot be converted.
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.