Convert audio — 12 formats, whole folders, nothing uploaded
Drop a folder's worth of files, convert each one to a different format if you want, normalise the loudness, write the tags, embed the artwork. Real ffmpeg compiled to WebAssembly, running on your machine — the same engine studios script, minus the terminal.
Nothing is uploaded — your audio never leaves your device.
Everything here is optional — leave it on “keep source” and the audio passes through untouched apart from the format change.
Loudness normalising measures the whole file first (EBU R128), so it is slower than a plain convert — and it is a real gain change, not a limiter.
Written into MP3, FLAC, OGG, AAC and ALAC outputs. Leave a field blank to leave it out.
Track numbers set to auto number the batch in queue order. Artwork embeds into MP3, FLAC, AAC and ALAC — the other formats carry no cover-art slot and will simply ignore it.
Placeholders: {name} original filename · {title} {artist} {album} from the tags tab · {n} queue number · {format} output format.
Presets remember every setting on all three tabs, on this device only. The page URL carries them too — copy the link to hand the exact setup to someone else.
Per-file overrides live on each row above: use the format dropdown on a row to send that one file somewhere different from the rest of the batch.
This converts anything. The studio remembers it.
AudioEncode in the studio keeps every converted master in one permanent library — searchable, re-exportable, and shared with the rest of the suite. Sign up and bring your catalog: 3 full packs free.
A real converter, not an upload form
Most "online converters" are upload forms in front of a server running ffmpeg. This one skips the middleman: the same ffmpeg engine is compiled to WebAssembly and runs inside your browser tab. That's why there's no queue, no file-size upsell, no "your download is ready" email — and why a private demo or an unreleased master can be converted here without ever existing anywhere but your machine.
Picking a format is simpler than the internet makes it: MP3 at high quality for anything that needs to play everywhere; AAC when it's headed for Apple or streaming; WAV or FLAC when you'll edit or archive it; ALAC when you want lossless that iOS will actually open. When in doubt, convert a copy — the original never changes.
The deeper controls sit behind the three tabs under the queue. Audio handles sample rate, bit depth and channels, plus loudness normalising to an EBU R128 target — the same measurement streaming platforms use — and trim, fade and leading-silence removal. Tags & artwork writes title, artist, album, year, genre and track into the output and embeds a JPEG or PNG as cover art. Batch & naming builds output filenames from those tags, saves the whole setup as a preset, and decides whether the run lands as one ZIP or as separate files. Any single row can also be sent to a different format from the rest of the batch.
Frequently asked questions
How do I convert audio without uploading it?
This converter runs ffmpeg — the industry-standard audio engine — compiled to WebAssembly inside your browser. Your files are read locally, converted locally, and downloaded locally. Nothing touches a server, which also means no file-size games, no queues, and no privacy question to ask.
What formats can it convert between?
In: almost anything ffmpeg can read — MP3, WAV, FLAC, OGG, M4A/AAC, Opus, AIFF, WMA, WavPack and more. Out: twelve formats — MP3, WAV, FLAC, OGG Vorbis, AAC, ALAC, AIFF, WavPack, CAF, MP2, AC-3 and WMA — each with its own bitrate, quality or compression control. You can also give any single file its own output format inside one batch.
Can it write tags and album artwork?
Yes. Set title, artist, album, year, genre, track and comment, and attach a JPEG or PNG as embedded cover art. Artwork is written into MP3, FLAC, AAC and ALAC outputs. You can also copy the tags already inside each source file instead of typing them again.
Why does it download a 10 MB engine first?
That's ffmpeg itself. It loads once, on your first convert — never on page load — and your browser caches it for a year, so every later visit converts instantly, even offline on some browsers.
Is there a file limit?
No batch cap. 80 MB per file keeps the browser comfortable, and the engine restarts itself every few files so long runs stay stable. Batches download as a single ZIP; single files download directly.
Will converting MP3 to WAV improve the quality?
No — a WAV made from an MP3 is just the MP3's data in a bigger box. Converting only preserves quality downward or sideways; it can never restore what a lossy encode removed. Check any file's real quality with our MP3 Quality Checker.