How to convert WMV to MKV
- Click Choose files or drop your WMV video into the box above.
- Keep the default quality, or choose a target size, resolution or frame rate.
- Click Convert and download the MKV when it is ready.
WMV vs MKV
| WMV | MKV | |
|---|---|---|
| Usual codecs | Windows Media Video 7/8/9 with WMA audio | Almost anything: H.264, HEVC, AV1, VP9 video; AAC, AC-3, DTS, Opus, FLAC audio; multiple subtitle and audio tracks |
| Plays on | Windows Media Player; not supported on Mac, iPhone, Android or in browsers | VLC, Plex, Kodi and most PCs; not supported by iPhone, iPad, QuickTime, many video editors and most websites |
| Best for | Old Windows Movie Maker projects and archives | Movies and TV episodes with several audio and subtitle tracks |
| Introduced | 1999 by Microsoft | 2002 by the Matroska open-source project |
About WMV and MKV
What is WMV?
WMV was Microsoft’s main video format in the Windows XP era, produced by Windows Movie Maker and many old cameras and screen recorders. Macs, phones and browsers cannot play it, so old WMV videos are best converted to MP4.
- Plays on older Windows PCs
- No support on Mac, iPhone, Android or the web
- Obsolete
What is MKV?
MKV is a flexible open container that can hold almost any video and audio codec, several audio languages, subtitles and chapters in one file. That makes it popular for movies, but iPhones, QuickTime, iMovie, many editors and most websites do not accept MKV — converting to MP4 makes it play everywhere.
- Holds any codec
- Multiple audio and subtitle tracks, chapters
- Open and royalty-free
- Not supported on Apple devices, many TVs and editors
- Rejected by most upload sites
Why GlideConvert?
- Private by design. Your files are converted on your own device by your browser — they are never uploaded to a server. That keeps them private, avoids upload waits and means there is no queue.
- Fast. Images convert in a fraction of a second; video uses your device’s hardware encoder and is often simply repackaged without re-encoding.
- Free. No sign-up, no watermark. 10 images, 5 audio files or one video at a time — Pro lifts the limits and removes ads.
Frequently asked questions
Will converting WMV to MKV lose quality?
Often not at all. If the WMV file already contains video and audio that MKV supports (H.264 video and AAC audio are the most common), they are copied as-is: no quality loss, and even a large file converts in seconds. Otherwise the video is re-encoded at high quality — choose a quality level or a target file size in the options.
How long does converting WMV to MKV take?
Usually much less than the length of the video: modern browsers encode video with your device’s hardware. WMV needs a universal decoder (FFmpeg compiled to WebAssembly, a one-time ~32 MB download) which is slower — expect roughly real-time speed for HD video.
Is WMV still worth keeping?
WMV is obsolete — only Windows Media Player plays it reliably. Converting to MP4 keeps your videos watchable on any device for years to come.
Is there a file size limit?
On the free plan each video or audio file can be up to 500 MB and each image up to 100 MB. With Pro the limit is 4 GB per file. Because everything happens on your device, the practical limit for very large files is your device’s memory.
Are my files uploaded to a server?
No. GlideConvert runs entirely in your browser: images are processed with the browser’s built-in codecs and WebAssembly, video and audio with hardware-accelerated WebCodecs (or a WebAssembly build of FFmpeg for older formats). Nothing is sent anywhere — you can even disconnect from the internet once the page has loaded.
Does it work on iPhone, Android, Mac and Windows?
Yes. It works in any up-to-date browser — Chrome, Edge, Safari, Firefox or Samsung Internet — on phones, tablets and computers, with nothing to install. Long or 4K videos convert faster on a computer than on a phone.