Step 1: Supply your MKV files using the button above or by haul and lay.
Step 2: Click the 'Convert' button to start the conversion.
Step 3: Get your converted WebM files.
MKV to WebM Conversion FAQ
What does the MKV to WEBM converter do?
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It transcodes a MKV video into the WEBM container. Resolution, frame rate, and aspect ratio are preserved by default — useful when you need a different format for a target player without quality loss.
Will resolution and frame rate be preserved in the WEBM?
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Yes. MKV → WEBM keeps resolution, frame rate, and aspect ratio unchanged by default. To change them, use the Resize or Speed tool on the result.
Is the MKV to WEBM conversion reversible?
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You can convert the WEBM back to MKV on this site. If either format involved is lossy, the round-trip is not bit-perfect even though it is visually or audibly close.
Will the converted WEBM be a different size than the MKV?
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Modern codecs compress better, so WEBM from a legacy MKV is typically 30-60% smaller at equivalent quality. Conversions in the opposite direction can grow the file.
Can MKV be converted to WEBM without re-encoding the video?
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Yes, and it is the fast path. MKV and WEBM share the same underlying box structure, so the video and audio streams are copied across byte-for-byte and only the container wrapper is rewritten. Nothing is decoded and nothing is re-compressed, so a feature-length file finishes in under a minute instead of half an hour, with output quality identical to the source. MKV is Matroska, an open container designed in 2002 with no licensing restrictions and no ceiling on what it can hold. WebM is a strict subset of Matroska that Google published in 2010 specifically to give HTML5 video a royalty-free container.
Is WEBM worth targeting for a video on a web page?
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For a page you control, yes. WEBM was built for exactly that job — it plays inline in every current browser with no plugin, no licence fee and no patent exposure, which is why it became the default for embedded and background video. Away from the browser it is the weaker choice: editing software, phone galleries and televisions largely ignore it, so it is a delivery format rather than a storage one. Keep the master in something else and publish this. WebM plays natively in every modern browser with no plugin, no licence fee and no patent exposure, which makes it the default for web-embedded video.
My MKV has several audio tracks — do they all survive into the WEBM?
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Not dependably. MKV stores multiple audio streams as first-class tracks, but WEBM playback support past the first track is inconsistent, so most players will only ever expose one. Choose the track you actually want before converting; the others are better extracted to their own files than left in a container that hides them. MKV is the archival container of choice because it stores unlimited audio tracks, soft subtitles, chapter markers and cover art in one file. WebM is a poor fit anywhere outside a browser — video editors, phones’ native galleries and Smart TVs largely ignore it.
My MKV files came from ripping discs — will they convert cleanly?
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Cleanly, yes, but check what is inside first. A rip usually carries more than the picture — often several audio languages, sometimes a subtitle track or chapter marks — and whether those survive depends entirely on what the WEBM can hold, not on the rip. The other thing to know is that the encode already happened: the ripper chose a bitrate years ago and no conversion can recover detail it discarded, so if the discs are still around, re-ripping beats re-encoding.
Will the WEBM play in a browser when the MKV would not?
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Yes, and that is usually the whole reason for the conversion. An MKV embedded in a web page either shows a broken player or forces a download, because browsers ship no decoder for it. WEBM plays inline through the native HTML5 video element with no plugin and no external application.
Is there a file-size limit when converting MKV to WEBM?
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Anonymous uploads are capped at a generous default; signed-in free accounts get a higher cap, and Pro accounts have no per-file limit. Browser memory is usually the practical constraint long before our server-side limits kick in.
Can I batch-convert several MKV files to WEBM at once?
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Yes. Drop or pick multiple MKV files in one upload — the converter processes them in parallel and returns a ZIP of the WEBM results. There is no need to repeat the upload step per file.
What happens to my MKV files after the conversion?
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Uploaded files and WEBM outputs are auto-deleted after a short retention window. We do not inspect, share, or train on user files. Direct download links are time-limited and tied to your session.
