Some tracks whisper, others shout. LevelAudio brings every MP3, WAV and FLAC in a folder to one volume — no re-encoding. Free, in your browser.
Any folder — subfolders, mixed formats and thousand-track collections welcome.
Every track gets a loudness and true-peak reading. You see the numbers before a single byte is written.
Quiet tracks come up, loud ones come down, the mix stays as mixed. A/B any track before you commit.
normalized/ folder.Network tab — it stays quiet.)No. LevelAudio applies pure gain: the whole track moves up or down together, like turning the volume knob once and leaving it. No compression, no limiting, no pumping — the quiet intro and the loud chorus keep exactly the distance the mix gave them. If a track can't reach the target without its peaks hitting the ceiling, it gets less gain and the app tells you, rather than squashing it.
Loudness isn't peak level — it's how loud a track feels. Two tracks with identical peaks can sit worlds apart, which is why volume-knob matching never quite works. LUFS measures the felt loudness the way broadcasters and streaming platforms do (K-weighted, per ITU-R BS.1770 / EBU R128), and LevelAudio shows you every track's reading before it touches anything.
−14 LUFS (the default) matches Spotify, YouTube and most streaming platforms and is a good all-round choice for personal libraries. −16 LUFS is the common recommendation for podcasts. −23 LUFS is the EBU R128 broadcast standard. All targets are enforced with a true-peak ceiling so nothing clips.
The gentlest one that works, shown per file in the app. MP3: only the gain field in each frame is rewritten (the mp3gain technique) — no re-encode. WAV and all measurement: hand-written BS.1770-4 DSP, sample-exact at the file's own bit depth, off the UI thread. Everything else — FLAC, odd encodings, hour-long recordings — falls back to a bundled FFmpeg (WebAssembly) with two-pass EBU R128 loudnorm. It loads once and runs on your device, like the rest.
MP3 volume can be changed by rewriting a gain field inside each frame instead of decoding and re-encoding the audio. Quality is untouched, tags and album art are preserved byte-for-byte, and the adjustment is exactly reversible. The trade-off: it works in 1.5 dB steps, so tracks land within ±0.75 dB of the target — inaudible in practice. Prefer sample-exact? Switch MP3 handling to "exact re-encode" in the app.
FLAC is compressed, so a gain change means decoding and re-encoding. That happens at the file's own bit depth and sample rate with FLAC's lossless compression — you end up with a normal FLAC of the same quality class. It's still more invasive than the MP3 patch, which is why the app names the method used, per file.
Your browser opens them, measures and adjusts them in memory, and writes results back to your disk (or hands you a ZIP). Nothing is uploaded or stored anywhere else — there's no server side to this tool at all.
A modern browser. Chrome and Edge can write results straight back into the folder you picked (new "normalized" subfolder, or in place if you ask). Firefox and Safari read folders fine and hand results back as a ZIP download.
Yes. Your machine does the work, so each user costs us almost nothing. If LevelAudio saved your library an afternoon, there's a pay-what-you-want tip jar.