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 how Spotify's loudness normalization actually works 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:

• Integrated LUFS — the average loudness over the entire track. This is the number streaming platforms use for normalization. It's the one that matters most.
• Short-term LUFS — average loudness over a 3-second window. Useful for checking dynamics during mastering. If your short-term is always within 1 LUFS of your integrated value, your track is over-compressed.
• Momentary LUFS — average over 400 milliseconds. Shows you transient-to-sustain relationships. Rarely used for decisions but helpful for understanding why your integrated number is what it is.

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:

• MixDiagnose (free, browser-based) — upload your mix and get integrated LUFS, true peak, and platform-specific predictions in 30 seconds. No signup, no install. The LUFS checker tells you exactly whether Spotify, YouTube, or Apple Music will turn you down — and by how much.
• Youlean Loudness Meter 2 (free version) — a VST/AU plugin with integrated, short-term, and momentary LUFS plus a true peak meter. The free version lacks loudness range (LRA) but covers the basics.
• TDR Nova (free) — technically a dynamic EQ, but it includes a loudness meter. Not a dedicated meter, but if you already have it for EQ, the metering is a bonus.
• Reaper's built-in metering — if you use Reaper, it has LUFS metering built in via the JS plug-ins. No extra purchase needed.

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:

• Spotify: -14 LUFS integrated, -1 dBTP true peak
• YouTube: -14 LUFS integrated, -1 dBTP true peak
• Apple Music: -16 LUFS integrated, -1 dBTP true peak
• Tidal: -14 LUFS integrated, -1 dBTP true peak
• SoundCloud: -10 LUFS integrated (no normalization, but competitive loudness expected)

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.

The 2-minute pre-mastering LUFS check

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

1. Bounce your master to a WAV (don't check in real-time — measure the actual output file).
2. Upload to the LUFS checker or run it through Youlean. Read the integrated LUFS value.
3. Compare to your target. If you're aiming for -14 LUFS and you're at -9, you're 5 dB too loud. If you're at -18, you're 4 dB too quiet.
4. Adjust and re-bounce. Too loud? Reduce limiter ceiling or output gain. Too quiet? Increase limiter drive. Re-check.
5. Verify true peak. Make sure you're at -1 dBTP or below. Inter-sample peaks above -1 dBTP cause distortion after platform encoding.

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:

• Checking peak instead of LUFS. A peak meter at -0.1 dBFS tells you nothing about perceived loudness. Always check integrated LUFS.
• Mastering louder than the platform target. If Spotify will turn you down to -14, mastering to -8 and getting turned down 6 dB sounds worse than mastering to -14 directly. The gain reduction adds a limiter to your already-limited signal.
• 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.
• Trusting the DAW master meter. Most DAWs show dBFS, not LUFS. Don't confuse them — they measure different things.

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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