LUFS Loudness Meter
Drop a song, podcast or video to measure its integrated loudness in LUFS, true peak, loudness range and short-term and momentary maximums, following ITU-R BS.1770-4 and EBU R128. See at a glance how much Spotify, YouTube, Apple Music or a broadcaster would turn it up or down. Nothing is uploaded.
Last updated:
Showing a built-in test signal.
Streaming and broadcast targets
| Platform / standard | Target | Peak limit | Gain to reach it | True peak after gain | Verdict |
|---|
Targets are the commonly published normalization levels as of 2026; platforms can change them. "Gain" is how much a platform would turn your file up (+) or down (−).
How to use the LUFS Loudness Meter
- Drop a file on the box or click to choose a song, podcast episode or video. A built-in test signal is measured when the page opens so you can see how the results look.
- Read the integrated loudness: the big number is the loudness of the whole file in LUFS. Check that true peak stays below −1 dBTP.
- Play the file and watch the chart: the green line is short-term loudness, the light line momentary loudness. Click the chart to jump to a loud or quiet spot.
- Compare with targets in the table to see how much each platform would turn your file up or down and whether peaks would get in the way.
- Copy the report or download the CSV to keep the measurement with your mix notes.
How the loudness is measured
This meter follows ITU-R BS.1770-4, the standard behind EBU R128, ATSC A/85 and the normalization used by streaming services:
- K-weighting. Every channel passes through a high-shelf filter (about +4 dB above 2 kHz, modelling the head) and a high-pass filter around 38 Hz, recomputed for the file's own sample rate.
- Mean square per 100 ms. The filtered signal is squared and averaged in 100 ms steps. Channels are summed with weights: 1.0 for left, right and center, 1.41 for surround channels, and the LFE channel is ignored.
- Loudness. L = −0.691 + 10 × log10(Σ Gi × zi) LUFS. Momentary loudness uses a 400 ms window, short-term loudness a 3 s window.
- Gating for integrated loudness. 400 ms blocks overlapping by 75 % are kept if they are above −70 LUFS; then the average of those is taken, and blocks more than 10 LU below it are dropped too. The average of what remains is the integrated loudness.
- Loudness range. Short-term values above −70 LUFS and above (their average − 20 LU) are sorted; LRA is the 95th percentile minus the 10th percentile.
- True peak. The signal is interpolated at 4× the sample rate with a windowed-sinc filter and the largest absolute value is reported in dBTP.
A quick self-check: a stereo 1 kHz sine with a peak of −20 dBFS in both channels measures −20.0 LUFS, and the same tone in one channel only measures about −23 LUFS.
Loudness targets at a glance
| Where it plays | Integrated target | True peak | What happens to louder files |
|---|---|---|---|
| Spotify | −14 LUFS (Loud: −11, Quiet: −19) | −1 dBTP | Turned down; quieter tracks are raised only as far as peaks allow |
| YouTube | −14 LUFS | −1 dBTP | Turned down; quieter videos are not raised |
| Apple Music | −16 LUFS | −1 dBTP | Sound Check turns tracks up or down |
| Podcasts | −16 LUFS stereo / −19 LUFS mono | −1 dBTP | Usually played as delivered, so hitting the target matters |
| EBU R128 TV and radio | −23 LUFS ±0.5 LU | −1 dBTP | Must be delivered at the target |
| ATSC A/85 US TV | −24 LKFS ±2 LU | −2 dBTP | Must be delivered at the target |
Platform targets are the commonly published values as of 2026 and can change. Check the current delivery spec when a client or distributor gives you one.
Reading your results
- Integrated well above −14 LUFS (for example −8): streaming services will turn it down by 6 dB, so it plays no louder than a −14 LUFS master but has less dynamics.
- True peak above −1 dBTP: MP3, AAC and Opus encoding can create clipping. Lower the limiter ceiling to −1 dBTP (or −2 for very loud masters).
- PLR (true peak minus integrated loudness) shows how much punch is left. Under about 8 dB is heavily limited; 12 dB or more is open and dynamic.
- Short-term peaks far above the integrated value point to a single loud section (a drop, a scream, an ad). Click that spot on the chart to listen.
- To change the loudness of a file, use the Audio Normalizer, then measure the result here again.
Frequently asked questions
What is LUFS?
LUFS (Loudness Units relative to Full Scale) measures perceived loudness rather than peak level. The signal is K-weighted (a filter that boosts high frequencies a little and cuts very low ones, roughly like human hearing), the mean square is averaged over time, and the result is expressed as −0.691 + 10 × log10 of the channel-weighted mean square. One LU equals one decibel. LUFS and LKFS are the same unit with different names.
What LUFS should I master to for Spotify and YouTube?
Spotify and YouTube normalize music to about −14 LUFS integrated, Apple Music to about −16 LUFS. Louder masters are simply turned down, so mastering much hotter than −14 LUFS gains no loudness on those platforms and costs dynamics. Many engineers still master between −14 and −9 LUFS for style; keep true peak at or below −1 dBTP so lossy encoding does not clip.
What is the difference between integrated, short-term and momentary loudness?
Momentary loudness averages the last 400 ms, short-term loudness the last 3 seconds, and both update every 100 ms here. Integrated loudness covers the whole file, but ignores 400 ms blocks below −70 LUFS and then blocks more than 10 LU below the average, so silence and very quiet passages do not drag the number down.
What is true peak and why is it higher than the sample peak?
Sample peak is the largest stored sample value. When a digital-to-analog converter or a lossy encoder reconstructs the waveform, the curve between samples can rise above the samples themselves. True peak estimates this by oversampling the signal 4× and is reported in dBTP. Streaming services recommend keeping it at or below −1 dBTP (broadcast specs use −1 or −2 dBTP).
What does loudness range (LRA) tell me?
LRA describes how much the loudness varies over the file, in LU. It is the spread between the 10th and 95th percentile of the short-term loudness after gating (EBU Tech 3342). Heavily compressed pop often measures 3 to 6 LU, dynamic film or classical music 15 LU or more. Podcasts and speech usually aim for a small LRA so listeners don't need to touch the volume.
What loudness should a podcast be?
Most podcast hosting and app guidelines recommend about −16 LUFS integrated for stereo and around −19 LUFS for mono, with true peak no higher than −1 dBTP. Broadcast TV is quieter: −23 LUFS under EBU R128 in Europe and −24 LKFS under ATSC A/85 in the US.
Is my file uploaded?
No. The file is decoded with your browser's Web Audio API and all filtering, gating and peak detection runs in JavaScript on your device. Nothing is sent to a server.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.