Convert FLV to MKV

FLV 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

FLV

FLV (Flash Video) is a container format used to deliver video over the web using Adobe Flash Player. Although Flash has been discontinued, FLV files remain common in older video archives. FLV typically wraps Sorenson Spark or VP6 video and MP3 or AAC audio.

Developer: Adobe (Macromedia)
Initial release: 2002
Compression: Lossy
Color depth: 8-bit
Transparency: No
Animation: Yes

Best for

Recovering legacy Flash video archives
Migrating old web video content
Playing retro web animations
Archiving early-2000s online video
Converting old streaming clips

Pros

+Compact streaming for its era
+Wrapped common codecs like Sorenson Spark and VP6
+Widely used in historical web video
+Simple container structure

Cons

−Flash Player discontinued and unsupported
−Low maximum quality and 8-bit color
−No modern codec or HDR support
−Security risks in legacy Flash runtime

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 FLV to MKV

1
Select FLV 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.

FLV vs MKV

Property	FLV	MKV
Compression	Lossy	Lossy or lossless
Color depth	8-bit	up to 12-bit HDR
Multi-track	Yes	Yes
DRM support	No	No
Open format	No	Yes

When to use FLV vs MKV

FLV

Recovering legacy Flash video archives
Migrating old web video content
Playing retro web animations
Archiving early-2000s online video
Converting old streaming clips

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 FLV → MKV

Recovering legacy Flash video archives
Migrating old web video content
Playing retro web animations
Archiving early-2000s online video
Converting old streaming clips
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 FLV to MKV free?

Yes. This FLV → 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 FLV 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 FLV files uploaded to a server?

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

Can I convert multiple FLV files at once?

Yes — batch conversion is supported. Add as many FLV 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 FLV 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 FLV file. Avoid repeated re-encoding to keep the best quality.

Does MKV support transparency?

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

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

Both formats use comparable compression, so the MKV output will be similar in size to your FLV 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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