RMS and LUFS
Also known as: loudness
RMS measures the raw average energy of audio; LUFS measures loudness the way people actually perceive it, which is what streaming platforms target. Matching a LUFS target keeps your audio as loud as everything else without being turned up or down.
Why it matters
Loudness is where a lot of amateur audio gives itself away: too quiet next to everything else, or crushed and harsh from being pushed too hard. LUFS matters because platforms normalize to it. If you deliver above or below their target, they turn you down or up, so matching the target is how you stay at parity and keep control of your sound.
In practice
Measure integrated LUFS and true peak on the finished file. Common targets are around -14 LUFS for YouTube and -16 for many podcasts, with true peak kept below a safe ceiling so playback does not clip. Match the target rather than chasing maximum loudness.
How Vocast handles this
Vocast's free loudness tool measures LUFS and true peak and matches your audio to a target for YouTube, podcasts, or broadcast, in your browser.