LUFS vs RMS comes down to one difference. Both measure the average level of your audio, but RMS measures raw signal power and treats every frequency the same, while LUFS measures loudness the way human ears hear it. LUFS is also the scale Spotify uses to set playback volume, so when you want to know how loud your song really is, read LUFS.

Below you’ll find what each one means in plain words, the differences side by side, how loud your master should be for Spotify and YouTube using only the numbers they publish, and how Max makes a master loud without wrecking it.

What is RMS in audio?

RMS stands for root mean square. It’s a way to average the level of a sound wave over a short window of time, usually a fraction of a second, and around 300 milliseconds on many meters. A peak meter only shows the single highest point of the wave. RMS shows the average power, which is much closer to how loud a sound feels.

So does a higher RMS mean louder? Usually, as long as you compare similar sounds. RMS has two weak spots, though. It treats all frequencies the same, but your ears don’t: we hear the upper mids, where vocals and snares live, far more easily than deep bass. A bass-heavy mix can show a high RMS number and still sound quieter than that number suggests. And RMS meters don’t all follow one standard, so two meters can show different numbers for the same song.

The gap between the peak level and the RMS level has a name, too. It’s called the crest factor. A big gap means punchy, dynamic audio. A tiny gap means the peaks have been squashed flat.

What is LUFS?

LUFS stands for loudness units relative to full scale. Full scale is the very top of a digital meter, 0 dB, so LUFS readings for music are negative numbers, and closer to zero means louder. One LU is the same size as one decibel. A song at -9 LUFS is 5 dB louder than one at -14 LUFS. You’ll also see LKFS, which is the same unit under the name the ITU standard uses.

Before it measures anything, a LUFS meter runs your audio through a filter called K-weighting. It turns the deep bass down and gives the highs a small lift, to match how people hear. That filter is the big thing RMS doesn’t have. LUFS comes from a broadcast standard, ITU-R BS.1770, which European broadcasters use as EBU R 128, so every meter that follows it shows the same number.

A LUFS meter such as the free Youlean Loudness Meter shows several readings at once. In this frame from Max’s video, short-term (1) covers the last 3 seconds and integrated (2) covers the whole song so far. Momentary max (3) is the loudest 0.4-second moment. True peak max (4) is the real highest point of the wave, including the bits between samples. The integrated reading skips silence and very quiet parts, so a long fade-out doesn’t drag it down. Loudness targets, like Spotify’s, use integrated LUFS.

LUFS vs RMS: the key differences

Here’s the short version, side by side:

Max makes the same point in his loudness video: “the peak you see on the meter inside your DAW has nothing to do with how loud your music is actually perceived”. RMS gets closer than a peak meter does. But LUFS is built for the question you’re really asking, which is how loud your song sounds.

Can you convert RMS to LUFS?

Not with a formula. Because LUFS weights frequencies and RMS doesn’t, the same RMS reading can mean different LUFS readings. A bass-heavy song and a bright song can share an RMS number and still land at different LUFS. The only reliable way is to measure LUFS directly.

The meter is free. Max uses the Youlean Loudness Meter, whose free version shows integrated LUFS and true peak and works in FL Studio and most other DAWs. Put it last on your master channel, play the whole song from start to finish, and read the integrated number at the end.

How loud should my master be for Spotify and YouTube?

Here’s what each platform says on its own pages, then what Max does. Only numbers the platforms publish themselves are listed here.

Spotify

• Spotify adjusts tracks to -14 LUFS, measured with the ITU 1770 standard.
• It does this during playback. Your uploaded file isn’t changed.
• Louder masters are turned down, with no extra distortion. Quieter masters are turned up, and Spotify leaves 1 dB of headroom for its compressed formats.
• Premium listeners can pick Loud (-11 LUFS, with a limiter), Normal (-14) or Quiet (-19).
• The web player and third-party devices, like TVs and speakers, don’t use loudness normalization.
• Spotify’s advice is to aim for -14 integrated LUFS with true peak below -1 dB, and to keep true peak below -2 dB if your master is louder than -14 LUFS.

Source: Spotify for Artists, loudness normalization. For the mixing side of streaming, see our guide to mixing and mastering for streaming.

YouTube

YouTube doesn’t publish a LUFS target on its help pages. What it does document is Stable Volume, a setting that’s on by default and evens out the gap between quiet and loud parts while people watch. YouTube says it’s turned off for YouTube Music and official music videos, and viewers can switch it off. Source: YouTube Help, control video volume.

So there’s no official YouTube number to aim for. Measure in integrated LUFS and follow the same rules as everywhere else.

Apple Music

Apple’s Sound Check plays songs at about the same loudness, so a master made very loud plays back quieter. Apple’s mastering guide also recommends leaving at least 1 dB of headroom to avoid clipping. Sources: Apple Support and Apple Digital Masters.

What Max aims for

Max’s point is that “people are confused between distribution target and playback threshold”. -14 LUFS is where Spotify plays your song by default. It isn’t a rule for how loud to make it. On that default setting, a louder master is simply turned down, with no extra distortion, so Max masters as loud as possible before it starts to sound worse. For electronic music, that means at least -8 to -6 integrated LUFS.

A master that loud is exactly why Spotify’s -2 dB true peak rule matters, and it’s what the next section is about. One more number you’ll see is -23 LUFS. That’s the target for TV and radio programmes in the EBU R 128 broadcast standard, not a target for music on streaming services.

How to get a loud master that still sounds clean

In the video below, Max takes a track that starts distorting at about -10 LUFS and gets the same song to around -5 to -6 LUFS, cleaner and with no clipping. Here’s his process, step by step.

Step 1: Fix the mix first

Delete parts that fight for the same space, keep the low end from hogging the mix, sidechain to make room for the most important sound, tame peaks on single channels and groups, and keep everything below 120 Hz in mono. Max says these habits give you 80% of a clean, loud mix.

Step 2: Cut the lows under your lowest note

On the master, set a Parametric EQ 2 low cut (1) just under the lowest note your song plays, but never lower than 30 Hz. His track is in E, at about 41 Hz, so his cut sits a little higher. Leave LIN, the linear phase mode (2), switched off on this EQ, and don’t add oversampling here either. Max saves both for the final limiter.

Step 3: Make the low end mono

Wide bass can cancel itself out on mono speakers and leave dead spots in clubs. Max uses a mid/side EQ in Patcher and raises the side channel’s low cut (1) until everything under about 120 Hz is mono.

Step 4: Clip the stray peaks

A clipper simply chops the tops off peaks. Max uses the small GClip plugin right after the EQ. He pushes it until he can just hear the knock of the drums change, then backs it off 10%, with oversampling on and softness at 0%. Why clip before the limiter? Limiters try to be smart and soften a big snare hit to squeeze it under the ceiling. A clipper doesn’t think, which is exactly why Max likes it here.

Step 5: Compress each band

Use Maximus or a plugin like FabFilter Pro-MB. Click a band (1) and raise its PRE gain (2) by about 7 to 10 dB, so there’s more room to work with. Compress the band to shrink its dynamic range, then turn up POST (3) to make up the loss. If the lows came down from +8 dB to about +5, add about 3 dB back.

Step 6: Limit last, with true peak on

The limiter goes last. Max uses the maximizer in iZotope Ozone, but any true peak limiter does the job. Turn on true peak first and start with the output ceiling at -0.3 dB. Then raise the gain until you hear distortion, and back off.

Next, check what happens after the song is turned into a compressed file like AAC or MP3. Ozone has a codec preview for exactly this. In Max’s test the master clipped after conversion even with true peak on, and that is why loud masters need the lower -2 dB ceiling Spotify asks for.

Max’s last word on loudness is worth keeping: “Quality is the best volume booster”. Make music people want to turn up. If you work in FL Studio, our step-by-step guide on how to master in FL Studio walks through a full chain with stock plugins only. For the last two steps in more depth, read about true peak meters and compression vs clipping vs limiting.

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