Loudness (LUFS)How loud the whole track sounds to people. Streaming services and podcast platforms use it to set the volume of what you upload. The list under the numbers shows how far you are from the most common targets.
Loudness range (LU)How much the loudness changes through the track. Small values mean a steady, compressed sound. Large values mean a lot of quiet and loud passages.
Sample peak and true peakSample peak (dBFS) is the highest level in the file, where 0 dBFS is the maximum.
True peak (dBTP) also counts the peaks that appear between samples when the audio is converted back to sound, and it is the one that matters when you export to MP3.
ClippingThe sound hit the maximum for several samples in a row and was flattened, which is heard as distortion. The places where it happens are drawn in red on the waveform.
The sample rate and bit depth are read from the file itself whenever the format allows it. For other formats the browser converts the audio before it can be measured, and the tool tells you when that happens. The bitrate of MP3 files with a fixed rate and of WAV files is exact; for any other file it is an estimate from its size and duration.
Need to fix what you find? Use the LUFS Normalizer to set the loudness, or the Volume Booster to change the level. A file that already has clipping cannot be repaired, so it is best to lower the level before the clipping happens.