Normalize Audio Online
Processing entirely on your device — large files may take a moment.
The loudnorm filter measures integrated loudness (EBU R128) and applies dynamic correction to land the whole track at -16 LUFS — the level podcasts and streaming platforms normalize to. One pass replaces guessing boost amounts per file.
Batch-friendly: drop a whole album and every track comes out at the same perceived loudness — no more riding the volume knob between songs.
How to normalize audio
- 1
Select your files
Drag & drop your MP3 files onto the area above, or click to browse. You can add multiple files at once for batch conversion.
- 2
Convert instantly
Click "Convert to MP3". The conversion runs entirely inside your browser using WebAssembly — no upload, no queue, no waiting.
- 3
Download results
Download each converted MP3 file individually, or grab everything at once as a ZIP archive.
About the MP3 format
MP3 (MPEG-1 Audio Layer III) defined digital music: standardized in 1993, popularized by Napster and the first portable players, and freed of all patents in 2017. It is lossy psychoacoustic compression — it discards frequencies the ear supposedly won't miss — at bitrates from 128 to 320 kbps, with ID3 tags carrying title, artist and cover art.
Twenty years of competitors have failed to displace it, because playback support is absolute: every device that has ever played music plays MP3. At 320 kbps even critical listeners struggle to identify it in blind tests, though modern codecs reach the same quality at noticeably lower bitrates.
+Strengths
- ✓Plays on absolutely everything
- ✓Rich tag ecosystem (ID3, cover art)
- ✓320 kbps is transparent for most listeners
!Limitations
- −Lossy ceiling — never a mastering format
- −Less efficient than AAC/Opus at equal quality
- −Low-bitrate artifacts are audible and permanent
Frequently asked questions
Normalize vs volume boost — which do I need?
Boost when you know the multiplier you want (+50%). Normalize when you want every file to land at the same perceived loudness regardless of how it was recorded.
Does it remove dynamic range?
loudnorm applies gentle dynamic correction within your chosen loudness-range (LRA 11) — quiet passages stay quieter than loud ones, just more audible.
Is -16 LUFS right for music?
It is the podcast/online-video standard. Streaming music platforms normalize around -14, so -16 leaves a small safety margin and avoids their gain reduction.