Is this MKV to FLAC converter really free?

Yes. Up to 5 files at a time, no signup, no catch. The free tier adds a small watermark to image output — Pro ($9.99/mo or $49/yr) removes it, raises the file size limit to 500 MB, and unlocks unlimited batch conversion.

Are my files uploaded to a server?

No — and you can verify it yourself. Open DevTools → Network tab, then convert a file. You'll see zero upload requests. Everything runs right in your browser. We never see your files.

How long does conversion take?

Usually 1–3 seconds for a typical file. The very first conversion on a fresh page load may take 5–20 seconds while the converter engine loads — after that it's instant. Your CPU does all the work locally.

What is the file size limit?

Free: up to 10 MB per file, 5 files per batch. Pro: up to 500 MB per file, unlimited batch. If you're working with large videos or RAW photos, Pro is built for that.

Can I batch convert multiple MKV files at once?

Yes — drop multiple files at once (or Ctrl/Cmd+click to select them) and they all convert in parallel. Free accounts handle up to 5 files per batch; Pro has no limit.

What bitrate will the converted audio use?

We default to 192 kbps for MP3, 128 kbps for OGG/Opus, and 320 kbps for M4A/AAC. These settings are perceptually transparent — most listeners can't tell the difference in a blind test.

Will my metadata (ID3 tags, album art) be preserved?

Yes, when both formats support it. Tags carry over on conversions like MP3→M4A or FLAC→MP3. WAV has limited tag support, so some metadata may not transfer.

Can I get truly lossless audio from an MKV?

Yes — if the MKV contains a FLAC or PCM audio track (common in Blu-ray remux files), the converter extracts it as a bit-perfect FLAC file. If the source is AAC or AC3, the FLAC stores the decoded lossy audio without further loss.

Blu-ray remux MKV files have TrueHD or DTS-HD audio — can I extract those?

Yes — the converter re-encodes TrueHD/DTS-HD to FLAC at high quality. The result is lossless-quality audio, though technically a transcode from the original lossless codec.

How private is this converter?

Completely private — by design, not policy. There is no upload endpoint. Files are processed right inside your browser tab and disappear the moment you close it. We collect only anonymous page-view counts; your file content is never seen or stored.

MKV to FLAC Converter — Free, Online, No Upload

How to convert MKV to FLAC online

1
Drop your MKV file
Drag and drop your Matroska Video file onto the converter, or click to browse your files. You can select up to 5 at once. Nothing leaves your device — conversion happens right here in the browser.
2
Hit Convert — it happens locally
Click Convert and watch it go. There's no upload, no server queue, no waiting. The converter runs Matroska Video → Free Lossless Audio Codec entirely in your browser tab. Most files finish in 1–3 seconds.
3
Download your FLAC
Your Free Lossless Audio Codec file is ready. Click Download, or grab a ZIP if you converted a batch. Close the tab and everything disappears — no copies kept anywhere.

MKV vs FLAC: format overview

MKV

Matroska Video

Matroska.org · 2002

Compression: lossy
Transparency: No

✓ Supports virtually any codec combination
✓ Multiple audio tracks and subtitles per file
✗ Not natively supported by iOS or older devices

FLAC

Free Lossless Audio Codec

Josh Coalson / Xiph.Org · 2001

Compression: lossless
Transparency: No

✓ Lossless compression — identical to source
✓ 50–60% smaller than WAV with no quality loss

MKV magic bytes: 1A 45 DF A3

FLAC magic bytes: 66 4C 61 43

Why convert MKV to FLAC?

MKV files often carry high-quality audio tracks — lossless PCM, DTS-HD, or TrueHD — that are completely inaccessible outside of a media player like VLC or Plex. If you want to archive that audio, run it through audio analysis software, or add it to a lossless music collection, the MKV container stands directly in the way.

FLAC (Free Lossless Audio Codec) is the open standard for lossless audio. It compresses without any quality loss — every bit of the original audio is preserved and can be reconstructed exactly. FLAC is supported in Plex, Jellyfin, Kodi, foobar2000, Audirvana, and virtually all serious audiophile and archival software. It is the format of choice for music libraries where quality cannot be compromised.

When you extract audio from MKV to FLAC, the output quality is exactly what was in the MKV — no more, no less. If the source audio is already lossless PCM (common in Blu-ray rips), you get a perfect copy in a portable, indexed format. If the source is a lossy codec like AC3 or AAC, converting to FLAC preserves that lossy signal without any additional degradation — but does not restore what the original compression removed. FLAC files are large compared to lossy formats but significantly smaller than raw WAV.

Quality & file size: MKV to FLAC

Typical file sizes: MKV 200–800 MB → FLAC 20–40 MB.

Converting from lossy MKV to lossless FLAC will not recover detail the MKV codec already discarded — but the output will not degrade any further. This is useful when you need a lossless format for editing or compatibility without additional compression artifacts.

Color depth: MKV supports standard color, FLAC supports standard color.

Transparency: MKV does not support transparency. FLAC does not support transparency — transparent areas become solid white.

Frequently asked questions

Privacy: how FormatDrop handles your files

Your MKVfiles are converted 100% inside your browser. They are never uploaded to our servers, never stored, and never seen by anyone other than you. This isn't a privacy policy claim — it's an architectural guarantee: our server has no endpoint that receives file bytes.