L = −0.691 + 10 × log10(Σ Gi × zi)
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How does this tool work?
Normalize perceived loudness toward a LUFS target so separate recordings play at a more consistent level. Processing uses FFmpeg/WASM loudnorm and stays local in the browser.
The target ranges from −24 to −5 LUFS, with −16 LUFS selected by default. The loudnorm filter receives a true-peak target of −1.5 dBTP and a loudness-range target of 11 LU. Processing uses one pass, without the prior measurements required for two-pass linear normalization. Dynamic processing can therefore alter differences between passages and resample the audio, including to 192 kHz. Output is 16-bit PCM WAV; the original sample rate is not guaranteed. The target is a processing instruction, not a certified measurement of the resulting file. Measure loudness and peaks after export for a delivery with strict specifications. EBU R 128 recommends −23 LUFS for broadcast programmes; this tool’s default is a separate product setting. There is no final compliance measurement or before/after LUFS report on this page. A loudness target is not a fixed gain: processing also depends on peaks and how the programme changes over time. Complete silence does not become audible speech. Keep the original to judge transitions and background noise. A later lossy conversion can shift peaks, so measure the actual delivery file when a platform specifies strict limits. The tool supplies a processing step rather than certification that an arbitrary recording meets a broadcast specification.
How to use this tool
Import the audio
Choose the track you want to normalize.
Set a LUFS target
Choose a target between -24 and -5 LUFS.
Listen in context
Download the generated WAV and check its level in the environment where it will be used.
Audio loudness normalizer — Calculation reference
- L
- Integrated loudness in LUFS
- zi
- Mean energy after K-weighting, over retained blocks
- Gi
- Channel weights from BS.1770; LFE excluded
This expression describes loudness measurement over blocks retained after the BS.1770 absolute and relative gates, with K-weighting. It does not describe a constant gain applied by loudnorm.
Use cases
Multi-episode podcast
Bring episodes recorded at different times closer to the same perceived level.
Voice and interviews
Prepare recordings with different overall levels before editing or publishing.
Workspace chain
Normalize after trimming or EQ, then convert to the delivery format.
Examples
A common processing target
These are actual filter parameters, not measured output values or a guarantee that every source reaches exactly −16 LUFS.
Input
Target −16 LUFSResult
loudnorm parameters: I=−16, TP=−1.5, LRA=11A broadcast reference
−23 − (−16) = −7. A difference between targets does not predict constant sample gain in dynamic mode.
Input
Target −23 LUFS instead of −16 LUFSResult
Target lowered by 7 LUTips and best practices
- LUFS normalization measures perceived loudness and is not the same as simply increasing gain.
- A louder target cannot repair a source that is already clipped or distorted.
- Use the same target across a group of files when you want a more consistent listening experience.
Sources and references
- European Broadcasting Union, EBU R 128 — Loudness normalisation and permitted maximum level of audio signals (opens in a new tab), 2023Page in English
- FFmpeg project, FFmpeg Filters Documentation (opens in a new tab)Page in English
- ITU-R, BS.1770 — Algorithms to measure audio programme loudness and true-peak audio level (opens in a new tab), 2023Page in English
Frequently asked questions
What does LUFS mean?
LUFS is a standardized unit used to express the perceived loudness of audio programmes.
Does normalization remove differences between loud and quiet passages?
Single-pass dynamic processing can change differences between loud and quiet passages. It does not offer the detailed controls of a dynamics compressor or repair clipping already present in the recording.
Does the process follow a known reference?
The engine uses FFmpeg loudnorm, which is designed around the loudness-measurement principles of EBU R128.
Is the default −16 LUFS setting the EBU R 128 recommendation?
No. −16 LUFS is a product default. EBU R 128 recommends −23 LUFS for broadcast programmes; use the requirements of your destination rather than assuming one universal target.
Will the normalized WAV retain its sample rate?
That is not guaranteed. Dynamic loudnorm may output 192 kHz and the engine does not force conversion back to the original rate. Resample afterwards if your delivery specification requires it.
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