Convert WEBM to MKV

WEBM to MKV converter that runs entirely in your browser. 100% free, no signup, no upload — your files never leave your device. One-click batch conversion.

Conversions

Drop any file here or click to browse

All file types supported

About formats

WEBM

WEBM is an open, royalty-free multimedia container designed for the web, sponsored by Google. It is based on the Matroska profile and pairs the VP8/VP9 or AV1 video codecs with the Opus or Vorbis audio codecs. WEBM is built for HTML5 video playback and is supported natively by Chrome, Firefox, Edge and most modern browsers.

Developer: Google
Initial release: 2010
Compression: Lossy
Color depth: up to 12-bit HDR
Transparency: No
Animation: Yes

Best for

Embedding video in HTML5 pages
Web-native video streaming
Royalty-free video delivery
Browser-based video playback
Open-source video projects

Pros

+Royalty-free and open format
+Native HTML5 playback in modern browsers
+Pairs VP8/VP9/AV1 with Opus/Vorbis
+Efficient compression for web delivery

Cons

−Limited support in Safari historically
−Fewer hardware decoders than H.264
−Less common in professional editing tools

MKV

MKV (Matroska Video) is an open standard, royalty-free multimedia container that can hold an unlimited number of video, audio, subtitle and metadata tracks in a single file. Matroska is popular for high-definition content, anime, and movie archives because it preserves multiple language tracks and subtitle streams. MKV is supported by VLC, MPC-HC and most modern smart TVs.

Developer: Matroska Org
Initial release: 2002
Compression: Lossy or lossless
Color depth: up to 12-bit HDR
Transparency: No
Animation: Yes

Best for

Archiving HD movies with multiple tracks
Storing multiple subtitle languages
Anime and foreign film distribution
Preserving multiple audio streams
High-quality video libraries

Pros

+Open standard and royalty-free
+Holds unlimited video, audio, and subtitle tracks
+Supports lossless and lossy codecs
+Wide support in VLC and smart TVs

Cons

−Not universally supported on mobile devices
−Slightly larger overhead than streamlined containers
−Less ideal for web streaming than MP4

How to convert WEBM to MKV

1
Select WEBM files from your computer, Google Drive, Dropbox, a URL, or by dragging them onto the page.
2
Choose mkv — or any other format you need as a result (more than 200 formats supported).
3
Let the file convert, then download your mkv file right away.

WEBM vs MKV

Property	WEBM	MKV
Compression	Lossy	Lossy or lossless
Color depth	up to 12-bit HDR	up to 12-bit HDR
Multi-track	Yes	Yes
DRM support	No	No
Open format	Yes	Yes

When to use WEBM vs MKV

WEBM

Embedding video in HTML5 pages
Web-native video streaming
Royalty-free video delivery
Browser-based video playback
Open-source video projects

MKV

Archiving HD movies with multiple tracks
Storing multiple subtitle languages
Anime and foreign film distribution
Preserving multiple audio streams
High-quality video libraries

Use cases for WEBM → MKV

Embedding video in HTML5 pages
Web-native video streaming
Royalty-free video delivery
Browser-based video playback
Open-source video projects
Archiving HD movies with multiple tracks
Storing multiple subtitle languages
Anime and foreign film distribution
Preserving multiple audio streams
High-quality video libraries

Frequently Asked Questions

Is converting WEBM to MKV free?

Yes. This WEBM → MKV converter runs entirely in your browser and is completely free — no account, no credits, no watermark.

Which devices and platforms can I use to convert WEBM to MKV?

Any modern device with a current web browser: Windows, macOS, Linux, Android, iPhone and iPad. There is nothing to install — the conversion happens locally.

Are my WEBM files uploaded to a server?

No. Files never leave your device. The entire WEBM → MKV conversion runs locally in your browser, so your data stays private.

Can I convert multiple WEBM files at once?

Yes — batch conversion is supported. Add as many WEBM files as you like and convert them to MKV in one pass, then download the results together.

What is the maximum file size?

There is no fixed server-side limit because the conversion happens in your browser. Practical limits depend on the available memory and CPU of your device.

Will converting WEBM to MKV reduce the quality?

Because both formats use lossy compression, the MKV output will not bring back any quality that has already been lost in your WEBM file. Avoid repeated re-encoding to keep the best quality.

Does MKV support transparency?

No — MKV has no alpha channel. Transparent areas of your WEBM file will be filled with a solid background colour in the converted file.

How will the file size change after converting WEBM to MKV?

Both formats use comparable compression, so the MKV output will be similar in size to your WEBM file — typically within 10–20% of each other.

Related Conversions

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FREE

100% Free

No hidden fees, no subscriptions, and no limits. Enjoy complete access to all features gratis.

SIGNUP

No Signup Required

Start converting immediately without creating an account or sharing email address.

PRIVACY

Private & Secure

Your files never leave your device. All processing is completed locally for maximum privacy.

BATCH

Batch Conversion

Convert multiple files simultaneously to save time. Fast and efficient multi-file queue.

LOCAL

Runs in Browser

Utilizes advanced client-side WebAssembly technology to process files directly inside your tab.

FORMATS

200+ Formats

Supports a wide variety of formats including images, documents, audio, video, and more.

USER REVIEWS

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