Loudness Meter & Mastering
See your track's loudness the way streaming services measure it, find out if they'll turn it down, and master it to the right level in one click.
🔒 Your audio is never uploaded - it's processed right here in your browser.
Free sound packs
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How it works
Drop in your track
Your mix or finished song - it's opened by your browser, never uploaded.
See the numbers
Integrated LUFS, true peak, a loudness-over-time graph, and what Spotify, YouTube, Apple and others will do to it.
Master and compare
Pick a target, master in one click, A/B against the original, and download the result.
How to check LUFS and master a song for Spotify & YouTube
Streaming services turn every song to the same loudness, measured in LUFS. This free LUFS meter shows how loud your track really is, what Spotify, YouTube and Apple Music will do to it, and masters it to the right level in one click.
Load your track
Drop your finished mix or song (MP3, WAV, M4A, OGG or FLAC) onto the box above. It's measured in your browser.
Check the loudness
Read the Integrated loudness in LUFS and the True peak in dBTP. The graph shows how the short-term loudness moves through the song.
See what streaming will do
The Streaming services will… list tells you whether Spotify, YouTube, Apple Music and others will turn your song down, and by how much.
Pick a target and master
Choose a loudness target - Streaming (-14 LUFS), Apple Music (-16), Loud / club (-9) or Podcast / voice (-16) - and press Master to … LUFS. Gentle compression, a limiter and a -1 dBTP ceiling are applied.
Compare and download
Switch between Original and Mastered to A/B them at matched volume, then press Download mastered WAV.
Frequently asked questions
What is LUFS and why does it matter?
LUFS measures how loud music feels, not just how high its peaks go. Streaming services measure every song in LUFS and turn loud ones down to match - Spotify and YouTube to about -14 LUFS, Apple Music to about -16. Mastering too loud just gets you turned down (and squashed); too quiet and you sound weaker than the next song.
Is this real mastering?
It's a solid one-click loudness master: level to target, gentle glue compression, a fast limiter and a -1 dBTP ceiling so it survives streaming conversion. It won't replace a mastering engineer's EQ and judgement - but for demos, AI-generated songs and uploads it gets you to the right level cleanly.
Which target should I pick?
Streaming (-14) suits Spotify, YouTube, Tidal and Amazon. Apple Music leans to -16. Loud / club (-9) is for DJ sets and genres that need to hit hard - streaming services will turn it down. Podcast / voice (-16) is the usual spoken-word standard.
Is my track uploaded?
No - measuring and mastering both run inside your browser. Nothing is uploaded.
How accurate is the meter?
It follows the ITU-R BS.1770-4 / EBU R128 method (K-weighting and gating) and typically lands within a few tenths of a LU of professional meters. True peak is estimated with 4x interpolation.
Master songs as you make them
Swara Sound's studio saves a loudness target per band, and makes full songs free with the Swara Engine.
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