BYTETOOLS

LUFS Loudness Meter

Measure integrated LUFS, loudness range and true peak to ITU-R BS.1770-4, and compare against Spotify, Apple Music and broadcast targets. Nothing is uploaded.

Drop a mix, master or podcast episode hereThe file is decoded and measured in your browser — nothing is uploaded and nothing is changed.

What is the LUFS Loudness Meter?

The ByteTools LUFS Meter measures how loud a mix actually is, the way streaming platforms measure it.

  • Integrated LUFS to ITU-R BS.1770-4 with both the absolute and relative gates
  • Loudness range (LRA) to EBU Tech 3342, plus momentary and short-term maxima
  • True peak estimated with 4x oversampling, alongside plain sample peak
  • Comparison table with the gain needed for Spotify, Apple Music and EBU R128
  • Warns when true peak rises above -1 dBTP, where lossy encoding starts to distort
  • Read-only and fully local - your master is never uploaded or altered

How to use the LUFS Loudness Meter

  1. 1

    Drop a mix, master or podcast episode onto the box.

  2. 2

    Click Measure Loudness and wait while the file is decoded and analysed.

  3. 3

    Read the integrated LUFS, loudness range and true peak at the top.

  4. 4

    Check the targets table to see the gain adjustment each platform would need.

  5. 5

    Watch for the true peak warning if you are anywhere above -1 dBTP.

About the LUFS Loudness Meter

The ByteTools LUFS Meter measures how loud a mix actually is, the way streaming platforms measure it. It applies the K-weighting filters from ITU-R BS.1770-4, integrates 400 ms blocks at 75% overlap, and applies both the -70 LUFS absolute gate and the -10 LU relative gate to produce an integrated loudness figure for the whole file.

Alongside that you get loudness range to EBU Tech 3342, the momentary and short-term maxima, sample peak, and a true peak estimate from reconstructing the waveform at four times the sample rate. A table shows how far you are from the usual delivery targets and exactly how many dB of gain would land you on each one.

Nothing is changed and nothing is uploaded - this is a meter, not a processor, and it reads the file in your own browser. Figures are measurements rather than opinions, but platform targets do move over time, so confirm the current specification before you deliver a master.

Frequently asked questions

What LUFS should I master to for Spotify and YouTube?

Both currently normalise to around -14 LUFS integrated, Apple Music to about -16, and broadcast in Europe to -23 under EBU R128. Mastering much louder than the target simply means the platform turns you down, so there is little to gain from it.

What is the difference between LUFS, dBFS and true peak?

LUFS measures perceived loudness averaged over time using a filter that mimics human hearing. dBFS sample peak is just the highest sample value. True peak estimates what the waveform actually reaches between samples, which is what a converter or lossy encoder has to reproduce.

Why is my true peak higher than my sample peak?

Because the real waveform passes between your samples, and can rise above all of them. That is exactly what this meter reconstructs. It is why delivery specs ask for -1 dBTP rather than 0 dBFS - encoding to MP3 or AAC can push those inter-sample peaks higher still.

What does loudness range (LRA) tell me?

How much the loudness varies across the whole piece. A heavily compressed pop master might sit around 3 to 5 LU, while a dynamic classical recording can exceed 15. There is no correct value - it just tells you whether your dynamics match the genre you are aiming at.

Is this as accurate as a paid loudness plugin?

The gated integrated loudness follows the standard exactly and matches reference test signals to within a tenth of a LU. True peak is estimated with 4x oversampling rather than a longer filter, so treat it as accurate to a few tenths of a dB and leave a little headroom.

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