If you’ve ever uploaded a track to Spotify and noticed it sounded quieter than everything else — or uploaded a podcast episode and found it coming out distorted — you’ve already encountered LUFS. Understanding this single number will change how you produce, master, and deliver audio forever.
What Does LUFS Stand For?
LUFS stands for Loudness Units relative to Full Scale. It’s a standardized measurement of perceived audio loudness defined by the International Telecommunication Union in the ITU-R BS.1770 standard (currently on revision 4, often written as BS.1770-4).
The “relative to Full Scale” part means LUFS values are always negative. Zero (0 LUFS) represents the absolute maximum loudness a digital audio system can produce. Real-world audio always sits somewhere below that, so you’ll see values like −14 LUFS, −16 LUFS, and −23 LUFS.
LUFS vs dB — What’s the Difference?
The most common confusion is between LUFS and dBFS (decibels relative to full scale). Here’s the key distinction:
- dBFS measures instantaneous signal level — the peak amplitude at any single moment in time
- LUFS measures perceived loudness averaged over time, using a K-weighting filter that models how human hearing works
This matters enormously in practice. A track that has constant, ear-fatiguing compression might peak at −1 dBFS while measuring −8 LUFS integrated. A quiet orchestral piece with dynamic swells might also peak at −1 dBFS but only measure −22 LUFS integrated.
Both tracks have the same peak level but wildly different perceived loudness. LUFS captures the difference. dBFS alone does not.
The Three LUFS Measurements
When you analyze audio with a loudness meter, you typically see three values:
| Measurement | What it measures | Typical use |
|---|---|---|
| Integrated LUFS | Average loudness over the entire file | Streaming normalization target |
| Short-term LUFS | Loudness over the last 3 seconds | Live monitoring during mixing |
| Momentary LUFS | Loudness over the last 400ms | Real-time peak loudness monitoring |
When streaming platforms talk about their “target LUFS,” they always mean integrated LUFS — the average loudness of your entire track from start to finish.
How Streaming Platforms Use LUFS
Every major streaming platform runs a loudness normalization algorithm before audio reaches the listener. When you upload a track, the platform measures its integrated LUFS. If it’s louder than the target, the platform turns it down. On some platforms, if it’s quieter, they turn it up.
This means the loud master you spent hours perfecting will arrive at listeners’ ears at the same volume as everything else. The platform will undo your extra loudness. But the aggressive compression you used to achieve that loudness? That stays — and now sounds worse because it’s been turned down.
Platform Loudness Targets
| Platform | Target LUFS | True Peak | Normalization |
|---|---|---|---|
| Spotify | −14 LUFS | −1 dBTP | Up & Down |
| Apple Music | −16 LUFS | −1 dBTP | Up & Down |
| YouTube | −14 LUFS | −1 dBTP | Down only |
| Apple Podcasts | −16 LUFS | −1 dBTP | Up & Down |
| TikTok | −14 LUFS | −1 dBTP | None |
| −14 LUFS | −1 dBTP | None | |
| Amazon Music | −14 LUFS | −1 dBTP | Up & Down |
| Deezer | −15 LUFS | −1 dBTP | Up & Down |
Note that TikTok and Instagram don’t normalize at all — your uploaded audio plays exactly as-is. This makes hitting −14 LUFS even more critical for those platforms.
What Happens If Your Track is Too Loud?
Say you master a track to −8 LUFS (a common loudness war-era approach) and upload it to Spotify. Spotify targets −14 LUFS, so it will turn your track down by 6 dB before it reaches listeners.
The listener experience:
- Your track plays at the same volume as everything else ✓
- The heavy limiting and pumping compression you used is now clearly audible ✗
- Your track sounds less dynamic compared to well-mastered content ✗
- You’ve damaged your sound for no gain in perceived loudness ✗
The loudness war is over. Streaming platforms won.
What Happens If Your Track is Too Quiet?
Say you master a podcast episode at −22 LUFS. Apple Podcasts targets −16 LUFS, so it will boost your audio by 6 dB.
This might seem fine, but:
- Any peaks that were close to 0 dBFS before boosting will now clip and distort ✗
- Noise floor artifacts get amplified ✗
- This is why the true peak limit (−1 dBTP) is just as important as the integrated LUFS target
True Peak — The Other Number You Need to Know
True peak (measured in dBTP — decibels True Peak) is different from sample peak. Digital audio is stored as discrete samples, but when converted back to analog, the waveform is reconstructed between samples. The actual waveform can peak higher than the highest sample value — these are called intersample peaks.
Most streaming platforms cap true peak at −1 dBTP. ATSC broadcast (US television) uses −2 dBTP.
If your track has samples that hit 0 dBFS and you upload it to a platform that boosts by 4 dB, the reconstructed waveform will now exceed 0 dB, causing intersample clipping. This is audible as a brief, distorted crackling — and it destroys the perceived quality of your audio.
Always check both integrated LUFS and true peak before uploading.
How to Check Your LUFS Level
You have several options:
-
LoudFix (free, browser-based) — Upload your file and it measures integrated LUFS and true peak using the ITU-R BS.1770-4 algorithm, then exports a normalized version at any target you choose. No installation required.
-
DAW loudness meter — Most modern DAWs (Logic Pro X, Ableton Live, Pro Tools) have built-in loudness metering with LUFS display. Look for a plugin called “Loudness Meter” or similar.
-
Standalone tools — Youlean Loudness Meter (free), iZotope Insight, or Waves WLM Plus all provide detailed LUFS analysis.
How to Normalize Your Audio to a Target LUFS
The correct way to normalize audio for streaming is linear gain adjustment — applying a single gain change across the entire file to shift the integrated LUFS to the target, without touching dynamics.
Do not use compression or limiting to achieve your LUFS target after mastering. The mastering process should already have the dynamics you want. Normalization is just scaling the result to meet the platform’s spec.
LoudFix does this automatically: it measures your file, calculates the exact gain needed, applies it, checks the true peak, and clips any intersample peaks if needed. The result is a platform-ready file with the correct LUFS target and true peak ceiling.
Common LUFS Mistakes
Mistake 1: Mastering louder to “beat” normalization Streaming platforms normalize everything. A louder master doesn’t sound louder on streaming — it just sounds more compressed.
Mistake 2: Ignoring true peak Hitting the LUFS target but leaving true peaks at 0 dBFS will cause intersample distortion after platform processing.
Mistake 3: Using peak normalization instead of loudness normalization Peak normalization adjusts the file so the loudest sample hits a target (like −1 dBFS). Loudness normalization adjusts so the perceived loudness hits a target. These are completely different operations.
Mistake 4: Different LUFS targets for music vs. podcast Music typically targets −14 LUFS on most platforms. Podcasts target −16 LUFS on Apple Podcasts and Spotify. Make sure you’re hitting the right number for your content type.
The Bottom Line
LUFS is the loudness measurement that streaming platforms use to level-play your audio. The rules are simple:
- Target −14 LUFS for music on Spotify, YouTube, Amazon Music, and TikTok
- Target −16 LUFS for podcasts on Apple Podcasts and Spotify
- Keep true peak at or below −1 dBTP on all platforms
- Use linear gain normalization only — don’t compress your way to the target
Use LoudFix to measure, normalize, and verify your audio before every upload. It takes 30 seconds and ensures your audio sounds exactly the way you intended it to, on every platform.