Spotify, YouTube, Amazon Music and Tidal play music at about -14 LUFS, Deezer at -15 and Apple Music at -16, turning louder masters down to that level. A louder master doesn't play louder there, so master for the sound you want and keep the true peak under -1 dBTP. Drop your master on Loudness check to see its LUFS, true peak and how many dB each service turns it down.

What is LUFS?

LUFS (loudness units relative to full scale) measures how loud audio sounds, not just how high its peaks go. It comes from the ITU-R BS.1770 standard, which the EBU R128 recommendation builds on. The meter weights the frequencies roughly the way your ears do (lows count for less) and ignores silence and very quiet passages, so a long quiet intro doesn't drag the number down as much as it would otherwise.

One LU is one dB of change: a master at -10 LUFS is 4 dB louder than one at -14 LUFS.

There are three readings you'll see:

• Integrated loudness: one number for the whole track. This is the one streaming services normalise by, and the big number Loudness check shows.
• Short-term loudness: the last 3 seconds, useful for comparing a chorus to a verse.
• Momentary loudness: the last 400 ms.

What is true peak?

A digital file stores samples, but the waveform your speakers play runs smoothly between them, and it can rise higher than any sample. A true peak meter oversamples to catch those peaks between samples and reports them in dBTP.

It matters because streaming services encode your master to a lossy format (such as AAC or Ogg Vorbis), and encoding can push peaks higher. A master that peaks at 0 dBTP can clip once a service encodes it. Keep the true peak at -1 dBTP or lower. Spotify's own guidance, at the time of writing, is to go to -2 dBTP if your master is louder than -14 LUFS.

What is loudness range?

Loudness range (LRA, in LU) is how much the loudness moves through the track: the spread between its quieter and louder passages. A heavily limited club track might sit at 3-5 LU. A film score or a classical recording can go well past 15 LU. Neither is better: it's a measure of how dynamic the track is, and it helps you compare your master with a reference.

What do Spotify, Apple Music and YouTube do with loudness?

Each service plays every track at its own target loudness. Louder tracks are turned down to it. Some also turn quieter tracks up, but only as far as their peaks allow.

These are the targets Loudness check uses. Services change them from time to time, and listeners can change what they hear: Spotify lets listeners pick a louder or quieter level or switch normalisation off, and Apple applies it through Sound Check, a setting listeners control. Treat the table as how most people hear your music by default, not a guarantee.

Why louder isn't better after normalisation

Say you have two masters of the same song: one limited hard to -8 LUFS, one left at -14 LUFS.

On Spotify, the -8 master is turned down 6 dB and the -14 master is played as it is. They come out at the same level. The only difference left is that the loud one lost its dynamics on the way: transients squashed, the kick and snare with less punch, maybe audible distortion. On Apple Music both are turned down, and the loud one still sounds flatter.

A quiet master has the opposite problem, but a smaller one. A master at -18 LUFS with peaks at -4 dBTP:

• Spotify wants +4 dB but stops at +3 dB, where the peak reaches -1 dBTP. It plays a dB under the songs around it.
• Apple Music turns it up 2 dB, to its -16 target.
• YouTube, Amazon Music, Tidal and Deezer leave it as it is, 3-4 dB quieter than louder songs.

Loudness still matters outside normalised streaming. DJs play files as they are, so a club track at -14 LUFS sounds weak next to the tracks around it in a set. Downloads and listeners who switch normalisation off hear your master's real level. That's why a lot of dance and hip-hop masters are still loud on purpose.

How loud should I master?

There is no single right number. Here is roughly where released masters sit, so you know what you're comparing against:

Plenty of releases sit outside these. A practical approach:

1. Set your limiter's ceiling to -1 dBTP, with true peak detection on if it has it. Go to -2 dBTP for a master louder than -14 LUFS.
2. Pick a reference track in your genre that you like the sound of, and measure it the same way you measure yours.
3. Master until it sounds right next to the reference, not until it hits a number. If you're only louder than the reference because you pushed the limiter, the services will turn you down anyway.
4. Check what each service does to it. If Spotify turns your master down 6 dB, you gave up dynamics for nothing on Spotify. Whether that trade is worth it for club play is your call.

Low end eats loudness: a long, heavy kick or sub uses up headroom before anything else does. See how to make a kick drum for keeping it tight.

How to check your master with Loudness check

1. Open Loudness check at tools.aden.space/loudness, or search "loudness" or "LUFS" in ⌘K. No account needed, and the file never leaves your browser.
2. Drop your master (WAV, MP3, FLAC, AIFF or M4A) on the page, or press Upload a master. Measure the file you'll send to your distributor.
3. Read the results: LUFS (the integrated loudness), True peak (shown in amber above -1 dBTP) and Range (in LU).
4. Under On streaming services, see how many dB Spotify, Apple Music, YouTube, Amazon Music, Tidal and Deezer turn it down, or up for a quiet one. Point at a value for that service's rule.
5. Drop your reference track next and compare.
6. Happy with it? Save as track puts the file in Aden with its BPM and key. Without an account it waits in your browser while you sign up.

Getting ready to release? You'll also need an ISRC for each recording. More tools like this one are in free music tools for producers.

FAQ

What LUFS should I master to for Spotify?

Spotify plays music at about -14 LUFS and turns louder masters down to that level, so mastering louder doesn't make your song louder there. Master for the sound you want, keep the true peak under -1 dBTP, or under -2 dBTP if your master is louder than -14 LUFS, and compare it with a reference track in your genre.

Does Spotify turn up quiet songs?

Yes, but only as far as the peaks allow. Spotify raises a quiet master towards -14 LUFS until its true peak reaches about -1 dBTP and stops there. YouTube, Amazon Music, Tidal and Deezer only turn loud tracks down and leave quiet ones as they are.

What is the difference between LUFS and dB?

A dB reading on a peak meter shows the highest level of the signal. LUFS measures how loud the whole track sounds, weighted the way human hearing works and ignoring silence. Two masters with the same peak level can be several LUFS apart, and one LU of change equals one dB.

Should my true peak be -1 dBTP or -0.1 dBTP?

Aim for -1 dBTP or lower for streaming. Services encode your master to lossy formats, and encoding can raise peaks, so a master at -0.1 dBTP can clip after encoding. Spotify recommends -2 dBTP for masters louder than -14 LUFS.

Is my master uploaded when I check it?

No. Loudness check measures the file in your browser and it never leaves your device, unless you choose to save it to Aden as a track.