1Upload the FLAC audio files you want brought to a consistent loudness.
2There is nothing to set: the loudness is brought to -16 LUFS (EBU R128), with true peaks kept below -1.5 dBTP.
3Run the analysis; integrated loudness and true peak are measured before any gain is decided on.
4Download the normalized FLAC file.
Normalize FLAC Loudness FAQ
Does the source format affect normalisation?
+
It does. FLAC is lossless compression — bit-identical to the source on decode, at about half the size of WAV. That determines whether the corrected audio can be written back exactly or has to be re-encoded.
Anything specific to FLAC here?
+
Yes — FLAC decodes bit-identically to the source, so any number of edit-and-resave cycles cost you nothing in fidelity. Worth knowing when the goal is a consistent set rather than one file.
Can I run Normalize FLAC Loudness on several FLAC audio files at once?
+
Yes, though lossless files are large, so the batch is bound by upload bandwidth rather than by processing. Settings apply uniformly across the set.
Are bit depth and sample rate preserved?
+
Yes, unless you change them deliberately. A 24-bit/96 kHz source stays 24-bit/96 kHz — nothing is silently downsampled to 16/44.1, which is the failure mode that makes a master unusable.
Does Normalize FLAC Loudness cost anything?
+
No. Normalize FLAC Loudness is free without an account, and nothing is added to the audio. The upload and the result are deleted automatically about 24 hours after the job, which leaves time to download the result.
Is there a file size limit on Normalize FLAC Loudness?
+
Yes: free accounts process audio up to 15 MB per file — for uncompressed PCM that is roughly twenty minutes of CD-quality stereo, so it is a real limit here in a way it is not for MP3. If you are over it, converting WAV to FLAC first is the free fix — it is lossless and roughly halves the size.
Why does a PNG site host Normalize FLAC Loudness?
+
PNG.to is built around the format you use when you cannot afford to lose a pixel: lossless, alpha-capable, and the correct answer for screenshots, logos, line art and anything with hard edges. Image work is rarely one step: people arrive to change a format and leave needing the picture a different size, a different weight or a different shape. Running Normalize FLAC Loudness on the same upload pipeline, the same size caps and the same account is the whole reason it is here rather than on a fourth tab.
What should I do with the result once Normalize FLAC Loudness is finished?
+
The converter on this site moves images to and from PNG, JPG, WebP, GIF and SVG — which is the step where the decision about transparency actually gets made. That is the step most people actually came for, and doing it after Normalize FLAC Loudness rather than before it means the conversion works from the file you finally settled on.
Is Normalize FLAC Loudness here the same tool the sibling sites run?
+
The engines are shared — the same libraries, the same workers, the same limits. What differs is the advice, and the advice here starts from one fact about the format this site is named after: there is no quality slider to get wrong — a PNG round-trips bit-exactly, so the only thing edits cost you is file size. A PNG site is opinionated about where PNG is the right destination and where it is not, and that judgement is worth more than the button.
Do I need an account, and does anything get kept?
+
No account is needed. Uploads and results are kept for about 24 hours, which leaves time to download the result, and are then deleted automatically; nobody reads, lists or indexes them. Several files in one job need a paid plan.
