Check your track before you post it to Instagram, TikTok or Spotify — loudness (LUFS) against each platform's target, mono/phase compatibility for phone speakers, and a phone-speaker playback preview.
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Everything runs locally with the Web Audio API: your file is read and decoded in the browser, analyzed there, and never uploaded anywhere — open your browser's network tab while you use this tool and you'll see no request carrying audio data. Integrated loudness follows the ITU-R BS.1770-4 standard: each channel is K-weighted (a high-shelf filter followed by a high-pass filter), then loudness is measured in 400ms blocks with 75% overlap and gated in two stages — an absolute -70 LUFS gate, then a relative gate 10 LU below the average of what remains. This is the same method behind EBU R128 and the loudness meters built into most DAWs.
Mono compatibility is measured as the phase correlation between your left and right channels, from +1 (identical, perfectly safe in mono) through 0 (uncorrelated, wide) to -1 (fully out of phase — will cancel to near-silence when summed to mono). Phones, laptop speakers and many Bluetooth speakers sum to mono, so a track with heavy stereo widening or out-of-phase effects can lose bass and clarity exactly where most of your audience will actually hear it.
Want the terminology behind LUFS, true peak and headroom explained in plain language? See the Music Production Glossary. Need to check the key or chords instead? Try the Chord Progression Analyzer, or tune an instrument with the Online Tuner before you record.
What LUFS should my track be for Instagram, TikTok and Spotify?
Spotify and YouTube normalize to about -14 LUFS integrated. Instagram and TikTok don't
publish an exact figure, but independent measurements put them in the same -14 to -13 LUFS
range. Louder than that and the platform turns you down; quieter and it may turn you up,
which can expose noise or eat into your headroom.
What is mono compatibility and why does it matter for phone speakers?
Most phones, laptops and many Bluetooth speakers play audio in mono, summing left and right
together. Elements that are wide and out of phase can partially or fully cancel in that sum
— something that sounds huge in headphones can nearly vanish on a phone speaker. The
correlation meter shows how safely your stereo mix survives that sum.
Does this tool upload my audio file anywhere?
No. The file is decoded and analyzed locally with the Web Audio API. It is never sent to a
server — check your browser's network tab while you use it and you won't see an upload.
How accurate is the LUFS measurement?
It implements the ITU-R BS.1770-4 algorithm in full: K-weighting per channel, 400ms gated
blocks with 75% overlap, an absolute -70 LUFS gate and a relative -10 LU gate — the same
method EBU R128 and professional loudness meters use, not an approximate RMS calculation.
Can I hear how my track will sound on a phone speaker?
Yes. The Phone Speaker Preview plays your track through a filter chain that approximates a
small phone speaker's response — steep low-end roll-off, a narrower midrange and a presence
boost — so you can A/B your normal mix against how most of your audience will actually hear
it.
Is this an official compliance test for Spotify, Instagram or TikTok?
No. This is an independent measurement tool built on the published ITU-R BS.1770-4 standard
— it is accurate, but it is not an official or certified test run by any platform, and
platforms can change their loudness targets or processing at any time without notice. Use it
as a fast, reliable first check, and always do a final listen — and check your DAW's own
meters — before you release.
Spotify, Instagram, TikTok and YouTube are trademarks of their respective owners. Cloud Atelier is not affiliated with, sponsored by, or endorsed by any of them; loudness targets are based on independent, publicly available measurements.