How to Read a Loudness Meter: LUFS in Plain Language

A loudness meter shows five readings: momentary (M) over the last 400 ms, short-term (S) over the last 3 seconds, integrated (I) across the whole track, true peak in dBTP, and loudness range (LRA). Integrated is the number streaming platforms judge. Read all five free on the Loudness tab of BeamTracer's Audio Analysis Engine, in Chrome or Edge.

Hi, I'm Trina with BeamTracer.com — let's put names on the five numbers your loudness meter keeps showing you.

At some point someone told you your track needs to "hit −14 LUFS", you opened a loudness meter to check, and it answered with five different numbers, none of which was labelled "your track". M, S, I, dBTP, LRA. A graph. A histogram.

Here's the thing: every one of those readings answers a genuinely different question, and once you know which question each one answers, a loudness meter stops being a cockpit and starts being the most honest instrument in your session. That's the whole post. No manual required.

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What are the five numbers on a loudness meter?

Everything below is those five rows, expanded.

What does LUFS measure, and how is it different from RMS?

LUFS is a time-averaged loudness measurement, like RMS, with two fixes that make the average match your ears. If you grew up watching an RMS meter, you already understand LUFS — both average the signal's level over time instead of chasing peaks.

LUFS is frequency-weighted. Your ears don't hear all frequencies as equally loud, so the measurement runs through a filter curve (called K-weighting) that tips the scale toward what humans actually perceive — a bit more sensitivity up top, less rumble counted down low.

LUFS is gated. Silence and near-silence get thrown out of the average. An RMS reading of a track with a long quiet intro is dragged down by the intro; the LUFS integrated reading ignores what's effectively not programme. That's why LUFS is the number every streaming platform settled on.

What do momentary, short-term and integrated loudness mean?

They are three clocks on the same signal: momentary averages the last 400 milliseconds, short-term the last 3 seconds, and integrated everything since the last reset. Integrated is the one platforms act on; momentary and short-term are what you watch while the music plays.

All three clocks at once, live: the bright line is momentary, the filled area is short-term, the dashed line is the target — and the histogram underneath is quietly filing every second away.

One habit that will save you from bad readings: integrated loudness is cumulative, so reset before you measure. If you start a measurement mid-track, or leave the meter running across three different songs, the integrated number describes that whole accumulated mess, not your track.

What is true peak, and why is it not the peak in your file?

True peak (dBTP) is the highest level the reconstructed analog waveform reaches between your samples — which can be higher than any sample in the file. A sample meter reads the samples; true peak oversamples the signal the way the standard specifies and reads what the listener's converter will actually produce.

What does LRA (loudness range) tell you?

Loudness range measures how spread out your short-term loudness is over the session, in LU. A dynamic live set might read 15 LU; a brickwalled master reads 3–5. Neither is "correct" — LRA is a description, not a grade — but it tells you instantly which kind of track you're looking at.

One caveat the meter should tell you itself: LRA is statistical, so it needs about a minute of programme before the number means anything. A good meter flags the reading as settling until then instead of showing you a confident wrong answer.

If dynamics are the part you care about, there's a whole companion post on PSR, PLR and LRA — including the one threshold worth memorizing.

Can you measure a whole file without playing it through?

Yes. Drop an audio file onto the Loudness tab, or click ANALYZE FILE, and BeamTracer measures the entire track on your machine in a couple of seconds — integrated, true peak, LRA and the full history, always from start to finish. It is the reliable way to get an integrated number, because an offline pass can never be contaminated by a mid-track start or a forgotten reset.

Is there a free loudness meter that runs without installing anything?

Yes — BeamTracer's Loudness tab is a browser tab in Chrome or Edge, with every view, platform preset, file analysis and export free. Loudness metering used to mean a plugin purchase, and the free tiers ration exactly the parts you want. For comparison, as of this writing:

Youlean's free meter is genuinely good — it became the default recommendation for a reason, and if you want a meter docked inside your DAW, it's the right call. The browser meter's case is different: nothing to install, nothing gated, and it reads any audio you can get into a tab — including a file you just drag onto it.

BeamTracer reports loudness using the ITU-R BS.1770 and EBU R128 standards. Compare the same complete track with the measurement reset, then choose the workflow that fits your session.

How do you measure a track's loudness in BeamTracer?

Open the Loudness tab, start audio, and read M, S and I as they settle; click ANALYZE FILE when you want the whole-track answer instead of a live pass. Pick your platform in the TARGET card so every reading is judged against it, then export the session as CSV or JSON.

Next

• What Spotify actually does to your track — normalization up, down, and the true-peak cap nobody models
• How dynamic is your master? PSR, PLR and LRA — the numbers that survive normalization
• Level a multi-person livestream in the browser — the classic two-computer workflow, collapsed into a tab
• Best audio visualizers in 2026 — the rest of what lives behind that same A key

Five numbers, all named. beamtracer.com — see you in the next one.