Convert MP3 to FLAC
MP3 wrapped in lossless form — for the tools that demand FLAC, made on your own device.
Drop your video or audio here
or
MP4, MOV, WebM, MKV, AVI, MP3, WAV and more — any size, no upload
🔒 Files never leave your device — everything runs in your browser.
Honesty first: converting MP3 to FLAC does not improve the sound. What the MP3's compression discarded is gone permanently — the FLAC simply preserves what the MP3 contains, losslessly, from this point forward. Anyone promising "lossless quality" from an MP3 source is selling something.
The legitimate reasons are practical: an editing pipeline, DJ library, or archival system that accepts only FLAC; wanting a format with checksums and proper tagging; or standardizing a mixed collection. The conversion decodes the MP3 exactly and stores the result as FLAC, entirely in your browser, with nothing uploaded.
How it works
- Drop your file
Any common format, any size. Nothing is uploaded — the tool runs in your browser.
- Convert
Compatible files are repackaged instantly with zero quality loss; others are hardware-transcoded at high quality.
- Download
Your converted file is ready on your device — nothing to wait for, nothing to delete from a server.
Frequently asked questions
Will FLAC make my MP3 sound better?
No — and this page will not pretend otherwise. The FLAC contains exactly what the MP3 contained, preserved without further loss. Better sound needs a better source, not a bigger container.
Then why convert MP3 to FLAC at all?
Because some software insists on it — archival systems, DJ tools, editing pipelines with FLAC-only inputs. Converting satisfies the requirement while at least never making anything worse.
Why is the FLAC so much bigger than the MP3?
FLAC stores the full decoded audio losslessly — several times the MP3's size. That growth buys preservation and compatibility with FLAC-only tools, not quality.
Is my file uploaded to a server?
No. ConvertUno runs entirely in your browser on your own device. Your file never leaves your computer or phone — there is no upload at all.
Is it really free, with no watermark?
Yes. Processing happens on your device, so serving you costs us almost nothing — no watermark, no account, no file-size limit, no daily quota.