FLV
→
MKV

Convert FLV to MKV Online

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

FLV to MKV Converter

Upload your FLV file to convert it to MKV format

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How to Convert FLV to MKV

Follow these simple steps

1

Step 1: Upload Your File

Upload your FLV 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

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Step 4: Download Result

Download your converted MKV file when ready

Convert FLV to MKV - Complete Guide

Converting FLV to MKV stays in the video file family but changes the traits that decide size, quality, transparency, editability, or device support. FLV is a video format. Flash video. 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 FLV→MKV conversion, what is preserved, and when MKV is the better choice than keeping FLV.

What changes when you convert FLV 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 FLV content with less aggressive compression.

About the FLV format

FLV (Flash Video) was popular for web video before HTML5. Our converter transforms legacy FLV files to modern, widely-compatible formats.

  • Full name: Flash Video
  • Developer: Adobe
  • Compression: H.263/VP6 (Video), MP3/AAC (Audio)
  • Opens with: VLC, FFmpeg

Where FLV is strong: small files that streamed efficiently in the Flash era; once the standard for online video.

Typical FLV uses: legacy Flash web video, older online video archives.

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

  • One MKV limitation to keep in mind: not natively supported by browsers or many devices.

When to convert FLV to MKV

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

FLV vs MKV — format comparison

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

AttributeFLVMKV
TypeVideo fileVideo file
CompressionLossyFlexible (lossy or lossless)
Web-friendlyNoNo
Typical file sizeSmallLarge
Best forlegacy Flash web 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 FLV to MKV converter to your site

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

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

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Need the opposite conversion?

Convert MKV to FLV

Other FLV Conversions

More formats you can convert FLV to

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

Convert to MKV

Other formats you can convert to MKV

Convert MP4 to MKVConvert MOV to MKVConvert WEBM to MKVConvert AVI to MKVConvert M4V 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

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FLV to MKV FAQ

Converting FLV to MKV preserves the content faithfully; output also depends on the source file and any settings you choose.
Upload your FLV 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 FLV to MKV conversion runs in your browser on any device — Windows, Mac, Linux, iOS, or Android — with uploads and downloads over HTTPS.
FLV (Flash Video) is a video file format. FLV files can be played with various video players and media applications.
Upload your FLV 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 FLV 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 FLV 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.

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