Convert FLV to MKV online in seconds — free, with no sign-up. MKV is lossy and ideal for archiving films with multiple tracks; converted to MP4 for compatibility. Your files are encrypted and deleted automatically after 24 hours.
MKV
Matroska Video — A flexible container that holds multiple audio, video and subtitle tracks.
How to convert FLV to MKV
- 1Upload your FLV file
Click “Choose a file” or drag and drop your FLV file onto the page — no sign-up or email needed.
- 2Convert to MKV
MKV is already selected as the output. Open Options to fine-tune quality if you like, then click Convert.
- 3Download your MKV file
Your MKV file is ready in seconds — click Download to save it. Files are automatically deleted after 24 hours.
Frequently asked questions
Does converting FLV to MKV lose quality?
Converting FLV to MKV keeps your content intact. We use high-quality defaults so your MKV file looks as close to the original as the format allows.
Is the FLV to MKV converter free?
Yes — converting FLV to MKV is completely free. There's no watermark, no sign-up and no email required, and you can convert as many files as you like.
Are my FLV files private and secure?
Yes. Your uploads are encrypted in transit, processed privately, and automatically deleted within 24 hours. We never share, sell or look at your files.
Can I convert FLV to MKV on iPhone, Android, Mac or Windows?
Yes. The converter runs entirely in your browser, so it works on any device — iPhone, iPad, Android, Mac, Windows or Linux — with nothing to download or install.
How long does it take to convert FLV to MKV?
Most files convert in a few seconds. Larger files take a little longer, and your upload speed is usually the limiting factor. There's no queue and no waiting for an email.
What else can I convert FLV files to?
Besides MKV, you can convert FLV to AAC, AVI, FLAC, GIF, JPG, M4A and more — see the full list of FLV conversions below.
Other conversions
Last updated July 2026