Podcast loudness checker

Is your episode at the level the apps expect?

Drop in an episode to measure its loudness and true peak the way broadcast meters do (ITU-R BS.1770), check it against Apple Podcasts’ recommendation, and get the gain that fixes it. Hour-long MP3s are fine: the file is read a piece at a time, in your browser. Nothing is uploaded.

Drop your episode here

MP3, M4A, WAV, AIFF, MP4 and MOV at any length. Other formats (FLAC, Ogg…) up to 64 MB. Measured in your browser; nothing is uploaded.

What the platforms publish

Apple Podcasts is the only major podcast platform with a published loudness figure: around −16 LKFS, give or take 1 dB, with true peak no higher than −1 dBFS, measured to ITU-R BS.1770. LKFS and LUFS are the same unit under two names.

Spotify publishes −14 LUFS normalisation, but its page is about music tracks and albums and doesn’t mention podcasts. Nothing Spotify publishes for podcasters gives an episode figure. The tool shows what the music rule would do, and labels it as that.

YouTube never published its reference; about −14 LUFS is what measurement has shown, and it turns loud audio down but not quiet audio up. Amazon Music publishes nothing on loudness.

So −16 LUFS with true peak under −1 dBTP is the safe aim. Spotify and YouTube, if they normalise episodes the way they do music, play a −16 episode within 2 dB of everything else, and nothing gets turned up into its limiter.

Mono episodes

Many podcasts are mono, and BS.1770 measures a mono file as a single channel. The same voice copied to both channels of a stereo file measures 3 dB louder, though it sounds identical from two speakers. So a mono episode at −19 LUFS and a dual-mono one at −16 are the same loudness to a listener. Neither Apple nor Spotify says which reading they use for mono, so the tool gives both and tells you when they disagree about Apple’s target.

How it’s measured

Integrated loudness follows ITU-R BS.1770-4 with EBU R128 gating, checked against the EBU’s conformance tests (Tech 3341 and 3342) and against ffmpeg on real material, MP3s included. True peak is measured 4× oversampled. MP3, MP4/M4A, MOV, WAV and AIFF are read directly, a few megabytes at a time, so memory use doesn’t grow with episode length. MP3 and AAC audio is decoded by your browser.