How to Check LUFS for Free Before Mastering

July 26, 2026 · MixDiagnose Team · 6 min read

If you master a track without checking its LUFS first, you're flying blind. Spotify, YouTube, and Apple Music all normalize to different loudness targets — and if your track misses the target, the platform will turn it up or down for you, potentially introducing artifacts or making it sound weaker than a competitor's mix. The good news: checking LUFS is free, fast, and removes all the guesswork.

This guide covers what LUFS actually measures, the free tools available right now, the targets you need to hit, and a pre-mastering workflow that takes under two minutes.

What LUFS measures (and why dBFS isn't enough)

LUFS — Loudness Units Full Scale — measures perceived loudness using the ITU-R BS.1770 standard. Unlike dBFS (sample peak), which only tells you the highest digital sample value, LUFS accounts for how human hearing actually works: we're more sensitive to midrange frequencies (where vocals and snares live) than to extremes. A kick drum peaking at -0.1 dBFS might read as loud on a peak meter, but a vocal at -6 dBFS can sound louder to a listener because of where it sits in the frequency spectrum.

This matters because streaming platforms don't care about your peak level — they care about integrated LUFS. If you master to -8 LUFS, Spotify normalizes to -14 LUFS and turns you down 6 dB. You sound quieter than a competitor who mastered to -14 directly. Check our deep dive on for the full breakdown.

The three LUFS values you need to know

Any good LUFS meter gives you three numbers. Understanding the difference is critical:

If you only check one number, check integrated LUFS. That's what determines whether Spotify turns you up, turns you down, or leaves you alone.

Free LUFS checking tools

You don't need to pay for a metering plugin. Several free options exist, each with different strengths:

For most producers, the fastest path is the browser-based MixDiagnose LUFS checker — upload, wait 30 seconds, get the number. If you want real-time metering during mastering, add Youlean Loudness Meter to your master bus.

Loudness targets by platform

Once you can measure LUFS, you need to know where to land. Here are the current targets:

The safest universal target is -14 LUFS with -1 dBTP. If you master to -14, Spotify and YouTube leave you alone, and Apple Music turns you up 2 dB (which is fine — their limiter handles it cleanly). Going louder than -10 LUFS means every major platform turns you down, and the gain reduction makes you sound quieter than a properly mastered -14 track. For more on why this happens, see our full LUFS explainer.

What real mixes actually measure

Nearly half finished mixes are too quiet for streaming, not too loud. Across 66 finished mixes uploaded to MixDiagnose by 25 different producers, 32 (48%) sat below −14 LUFS — the level Spotify, YouTube and Amazon Music normalize to — and the median integrated loudness measured −13.52 LUFS, about −0.5 dB under that target. That is the opposite of the usual assumption. A mix under the target gets turned up by the platform, and a platform limiter working on a mix with no headroom left squashes its loudest moments relative to the rest, which is why a quiet master can sound more compressed on Spotify than the file you printed.

The same corpus shows a second, less obvious pattern. A large share of the mixes we measured sat within 0.3 dB of full scale — median sample peak −0.89 dBFS — and 27% sat at exactly 0.0 dBFS with no codec headroom at all. Pinned to the ceiling while quiet in average loudness is the signature of a limiter absorbing work the arrangement and gain staging should have done.

Practically: measure before you master. If you are −0.5 dB under the target with no headroom left, turning the limiter down does not fix the loudness — it has to come from gain staging upstream, or you trade quiet for squashed.

Figures come from 66 finished mixes uploaded by 25 different producers and stored in our own analysis database, deduplicated by content — a small sample, stated rather than generalized. Regenerated from the database by scripts/corpus_stats.py, never typed by hand.

The 2-minute pre-mastering LUFS check

Here's the workflow I recommend before you print any master:

That's it. Two minutes per check. No more guessing whether your master is "loud enough" — you have a number.

Common LUFS mistakes

Checking LUFS is simple, but producers still make these errors:

• Ignoring true peak. LUFS measures loudness; true peak measures clipping risk. You need both. Read our guide on true peak and why your mix is clipping for details.

After the check: what to do with the number

Once you know your integrated LUFS, the decision is simple. If you're at -14 and your true peak is at -1, you're done — ship it. If you're at -10 and you want to stay competitive on Spotify, either accept the turn-down or back off the limiter. If you're at -18, push the limiter harder — you have headroom.

The mistake is checking after you've already uploaded to distributors. By then it's too late. Check before you bounce, fix the number, then bounce. Two minutes saves a re-submission and weeks of waiting for stores to update.

For a broader view of where loudness fits in the pre-mastering workflow, see our pre-mastering checklist — LUFS is one of six checks you should run before printing.

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