Your DAW may tell you that your track never reaches 0 dBFS, but that does not necessarily mean the signal is completely safe from clipping after conversion or playback.
What is True Peak?
True Peak estimates the highest level the reconstructed analogue waveform can reach between digital samples. It is normally expressed in dBTP.
A normal sample peak meter only looks at the individual digital samples. True Peak analysis attempts to account for what can happen between those samples.
Why can the peak be higher than the sample value?
Digital audio stores discrete samples. When a digital-to-analogue converter reconstructs those samples into a continuous waveform, the waveform can rise above the highest stored sample.
These are commonly referred to as inter-sample peaks.
Why does this matter for streaming?
Audio can be encoded, decoded, resampled or processed before it reaches a listener. A master with very little peak headroom can therefore be more vulnerable to clipping or distortion during subsequent processing.
What True Peak level should you use?
There is no single number that applies to every mastering situation, but leaving sensible true peak headroom is a common professional practice.
Many engineers use a ceiling around -1 dBTP or lower when preparing material for lossy distribution.
True Peak is only one part of the picture
A safe True Peak reading does not automatically mean a master is ready. Loudness, dynamics, clipping, frequency balance and stereo characteristics also matter.
True Peak should be measured alongside the rest of the master, not treated as an isolated pass/fail number.
LoudCheck measures True Peak using an upsampled signal to help identify potential inter-sample peak issues.