Measure a song or an episode the way the streaming apps do — integrated loudness in LUFS, true peak and loudness range — then see how much Spotify and Apple Podcasts will turn it up or down. Measured in your browser; nothing is uploaded.
Music: silence is only checked at the start and end.
Measured entirely in your browser — your audio is never uploaded anywhere.
Your audio is decoded and measured entirely in your browser. It is never uploaded or stored by CAPTD and never leaves your device.
Do this automatically from your episode audio
Promoting an episode? Spotlight's Episode mode makes clips and audiograms with clean audio already at the podcast norm, and writes the posts for each platform.
Episode mode is part of the Spotlight workspace on CAPTD's paid plans — see pricing.
Open Episode modeDecodes the file in your browser and measures it per ITU-R BS.1770-4: integrated loudness over the whole file (gated, in LUFS), the loudest 400 ms (momentary) and 3 s (short-term), and the true peak with 4x oversampling. Loudness range follows EBU Tech 3342. The streaming preview applies each platform's published normalisation rule to your numbers.
Integrated loudness is the single number platforms normalise to. The true peak should stay under -1 dBTP so encoding doesn't clip. Loudness range shows how much the level moves; PLR (peak minus loudness) shows how much the peaks stick out above it.
LUFS (Loudness Units relative to Full Scale) measures loudness the way people hear it: the audio is filtered to match the ear's sensitivity (K-weighting) and averaged over time, ignoring silence. It's defined in ITU-R BS.1770, the standard streaming platforms and broadcasters use.
True peak is the highest point of the waveform including between samples, which is where a lossy encoder can push it past full scale.
Streaming apps play everything at a similar loudness. Knowing your file's LUFS tells you how much it will be turned down — and whether the loudness you fought for in the master survives at all.