WEBM
→
MKV

Convert WEBM to MKV Online

Convert WEBM to MKV online. Start with free daily conversions, no install, no watermarks, and visible job status.

WEBM to MKV Converter

Upload your WEBM file to convert it to MKV format

Loading converter...

How to Convert WEBM to MKV

Follow these simple steps

1

Step 1: Upload Your File

Upload your WEBM file by dragging and dropping or clicking to browse

2

Step 2: Select Output Format

MKV is automatically selected as the output format

3

Step 3: Start Conversion

Click the Convert button to start the conversion

4

Step 4: Download Result

Download your converted MKV file when ready

Convert WEBM to MKV - Complete Guide

Converting WEBM to MKV stays in the video file family but changes the traits that decide size, quality, transparency, editability, or device support. WebM is a web-focused video format designed for efficient playback in modern browsers. MKV is a flexible video container format often used for high-quality video, subtitles, and multi-track media. Below is what actually changes in a WEBM→MKV conversion, what is preserved, and when MKV is the better choice than keeping WEBM.

What changes when you convert WEBM to MKV

  • The video is re-encoded into the MKV format. Because re-encoding is not free, start from the highest-quality source you have and keep quality settings high.
  • Expect a larger output file: MKV stores WEBM content with less aggressive compression.

About the WEBM format

WEBM is an open video format designed for the web. It offers excellent compression and quality for HTML5 video. Our converter handles WEBM files with VP8/VP9 codecs.

  • Full name: WebM Video
  • Developer: Google
  • Compression: VP8/VP9 (Video), Vorbis/Opus (Audio)
  • Opens with: modern browsers, VLC

Where WEBM is strong: open format built for the web; efficient VP9/AV1 compression; plays natively in modern browsers.

Typical WEBM uses: web-embedded video, open-source playback, HTML5 video.

About the MKV format

MKV (Matroska Video) is a flexible container format that can hold multiple video, audio, and subtitle tracks. Our converter extracts and transforms MKV content.

  • Full name: Matroska Video
  • Developer: Matroska.org
  • Compression: Various (H.264, H.265, VP9)
  • Opens with: VLC, Plex, MKVToolNix

Where MKV is strong: stores multiple audio, video, and subtitle tracks; flexible, high-quality container.

Typical MKV uses: high-quality video libraries, multi-track and subtitled video.

What MKV keeps

  • MKV adds: stores multiple audio, video, and subtitle tracks.

Things to watch out for

  • MKV is less universally supported than WEBM — make sure your target player or platform accepts MKV before converting.
  • One MKV limitation to keep in mind: not natively supported by browsers or many devices.

When to convert WEBM to MKV

  • Convert WEBM to MKV for high-quality video libraries.
  • Convert WEBM to MKV for multi-track and subtitled video.
  • Pick MKV when you need flexible, high-quality container.

WEBM vs MKV — format comparison

A quick side-by-side of the structural differences between WEBM and MKV, so you can confirm this is the right conversion for your file:

AttributeWEBMMKV
TypeVideo fileVideo file
CompressionLossyFlexible (lossy or lossless)
Web-friendlyYesNo
Typical file sizeSmallLarge
Best forweb-embedded videohigh-quality video libraries

Privacy & Security

Files are handled for the conversion you request. Uploads and downloads use HTTPS/TLS, and temporary files are cleared after the processing and deletion window.

Add this WEBM to MKV converter to your site

Put a working WEBM to MKV converter on your own blog or website — free to embed. Both options below include a small link back to FreeFastConverter.

Embeddable widget (iframe)

Paste this where you want a live converter. Visitors can convert WEBM to MKV without leaving your page:

Widget Embed Codeiframe

Simple link badge

Prefer a lightweight button instead? Copy this HTML badge:

HTML Badge CodeLink

Need the opposite conversion?

Convert MKV to WEBM

Other WEBM Conversions

More formats you can convert WEBM to

Convert WEBM to MP4Convert WEBM to MOVConvert WEBM to AVIConvert WEBM to MP3Convert WEBM to FLVConvert WEBM to WMVConvert WEBM to 3GPConvert WEBM to MPEGConvert WEBM to MPGConvert WEBM to TSConvert WEBM to OGVConvert WEBM to 3G2Convert WEBM to ASFConvert WEBM to M4VConvert WEBM to AACConvert WEBM to WAVConvert WEBM to OGGConvert WEBM to FLACConvert WEBM to M4AConvert WEBM to WMAConvert WEBM to AIFFConvert WEBM to OPUS
View all WEBM conversions →

Convert to MKV

Other formats you can convert to MKV

Convert MP4 to MKVConvert MOV to MKVConvert AVI to MKVConvert M4V to MKVConvert FLV to MKVConvert WMV to MKVConvert 3GP to MKVConvert 3G2 to MKVConvert MPEG to MKVConvert MPG to MKVConvert TS to MKVConvert MTS to MKVConvert M2TS to MKVConvert VOB to MKVConvert OGV to MKVConvert ASF to MKV
View all MKV conversions →

Popular Related Conversions

Convert WEBM to MP4

WEBM to MKV FAQ

Converting WEBM to MKV preserves the content faithfully; output also depends on the source file and any settings you choose.
Upload your WEBM file, confirm MKV as the output format, and click Convert. Job status is shown while the file is processed, then you can download the MKV result.
Yes. You can start with free daily conversions, with no signup required for your first jobs and no watermarks on the output. Accounts and paid plans are available for higher-volume work.
No. The WEBM to MKV conversion runs in your browser on any device — Windows, Mac, Linux, iOS, or Android — with uploads and downloads over HTTPS.
WEBM (WebM Video) is a video file format. WEBM files can be played with various video players and media applications.
Upload your WEBM video to the converter, select your desired output format, and click Convert. The job status appears while the video is processed.
You can start with free daily conversions. Accounts and paid plans are available for higher-volume work, and downloaded files are not watermarked.
You can convert WEBM to proof-backed video containers such as MP4, WEBM, MOV, AVI, MKV, FLV, WMV, 3GP, OGV, ASF, plus audio outputs like MP3, WAV, AAC, FLAC, M4A, WMA, AIFF, and OPUS.
Yes! Our WEBM converter works on any device including smartphones and tablets.
Choose the output setting that fits your file-size and playback needs. Re-encoding can change quality depending on codec and bitrate.

Related tools

Convert WEBM to MKV Now

Start with 10 free daily conversions. No signup required for your first file jobs.

Convert Now