How do I convert MKV to WebM?

Drop your MKV file onto the converter above, make sure WebM is selected, and click Convert. When it's done, download the WebM file — it usually takes a few seconds.

Is it safe to convert MKV to WebM here?

Yes. MKV to WebM conversion happens entirely inside your browser using WebAssembly, so your file is never uploaded to any server.

Is the MKV to WebM converter free?

Yes — free with no watermark. Signed-out visitors can convert 25 files a day, and a free account raises that to 250.

Will converting MKV to WebM reduce quality?

WebM is a lossy format, but our defaults are tuned to be visually indistinguishable for most files. You can raise the quality under Options.

Can I convert multiple MKV files at once?

Yes. Add up to 5 files at a time without an account, 10 with a free account and up to 500 on paid plans, then download them individually or as a single ZIP.

Can I convert WebM back to MKV?

Yes — use our WebM to MKV converter. Note that converting back and forth between formats can't recover detail lost to lossy compression.

WebM→MKV MKV→MP4 MP4→WebM MKV→MP3 MOV→WebM MKV→WebP GIF→WebM MKV→MOV MKV→GIF AVI→WebM MKV→WAV WMV→WebM MKV→M4A MKV→AVI MKV→FLAC MKV→AAC MKV→OGG MKV→WMV MKV→Opus MKV→M4V MKV→FLV MKV→MPEG MKV→3GP MKV→WMA MKV→TS MKV→MPG MKV→AIFF MKV→AMR MKV→VOB MKV→M4B M4V→WebM 3GP→WebM FLV→WebM MPEG→WebM TS→WebM MPG→WebM MTS→WebM VOB→WebM M2TS→WebM APNG→WebM OGV→WebM MXF→WebM DivX→WebM 3G2→WebM RM→WebM RMVB→WebM F4V→WebM ASF→WebM PNG→JPG JPG→PNG PNG→WebP JPG→WebP WebP→PNG WebP→JPG HEIC→PNG HEIC→JPG MP4→MP3 PNG→JPEG JPG→JPEG JPEG→PNG JPEG→JPG PNG→PDF JPG→PDF PDF→PNG PDF→JPG HEIC→WebP MP4→WebP PDF→DOCX DOCX→PDF JPEG→WebP WebP→JPEG PNG→GIF JPG→GIF GIF→PNG GIF→JPG MP4→MOV MOV→MP4 WebP→PDF HEIC→JPEG WebP→GIF GIF→WebP HEIC→PDF MP3→WAV WAV→MP3 JPEG→PDF PDF→JPEG SVG→PNG SVG→JPG HEIC→GIF MOV→MP3 MP4→GIF GIF→MP4 JPEG→GIF GIF→JPEG PNG→AVIF JPG→AVIF AVIF→PNG AVIF→JPG MP3→M4A M4A→MP3 GIF→PDF SVG→PDF PNG→SVG JPG→SVG PDF→SVG SVG→WebP MOV→WebP MP4→WAV WebM→MP4 WebP→AVIF AVIF→WebP WebP→SVG SVG→JPEG MP4→MKV HEIC→AVIF MP4→M4A JPEG→AVIF AVIF→JPEG JPEG→SVG MOV→GIF GIF→MOV WebM→MP3 AVIF→PDF MP3→FLAC FLAC→MP3 MP4→AVI AVI→MP4 GIF→AVIF AVIF→GIF SVG→GIF GIF→SVG WebM→WebP MOV→WAV XLSX→PDF CSV→PDF EPUB→PDF PDF→EPUB WebM→MOV PNG→ICO JPG→ICO ICO→PNG ICO→JPG MP3→AAC WAV→M4A AAC→MP3 M4A→WAV MP4→FLAC AVI→MP3 MOV→MKV MOV→M4A DOCX→EPUB EPUB→DOCX CSV→DOCX PDF→TXT DOC→PDF TXT→PDF WebP→ICO ICO→WebP PPTX→PDF AVI→WebP

MKVWebM

Convert MKV to WebM

Free and private: MKV files are converted in your browser on computers; on phones, in our fast cloud and deleted automatically.

In your browser (fast cloud on phones)
No watermark
Batch & ZIP download

Need a smaller MKV? Compress MKV

How to convert MKV to WebM

1
Add your MKV files
Drag and drop MKV files onto the converter, paste them, or click to browse. You can add several at once.
2
Choose WebM
WebM is already selected. Open Options if you want to change quality, size or metadata.
3
Convert
Click Convert. Your files are converted right in your browser in seconds.
4
Download your WebM
Download each WebM file, or everything at once as a ZIP.

MKV vs WebM

From

MKV · Matroska Video

MKV is a flexible open container that can hold unlimited video, audio and subtitle tracks in nearly any codec.

Type: Video
Extension: .mkv
MIME: video/x-matroska
Best for: movies and series with multiple audio and subtitle tracks

Open standard

All MKV conversions →

WebM · WebM Video

WebM is an open, royalty-free video format designed for the web, using VP8/VP9 or AV1 video with Opus audio.

Type: Video
Extension: .webm
MIME: video/webm
Best for: video on websites and in browsers

Lossy compressionOpen standard

All WebM conversions →

Need it the other way around? Convert WebM to MKV.

MKV to WebM: frequently asked questions

Free, private and in your browser