Make audio louder
Make audio louder: choose the file, set the target loudness, save. The tool measures before and after and prevents clipping. Your file stays on your device.
Source: ITU-R BS.1770 – Algorithms to measure audio programme loudness and true-peak audio level. Updated: .
How it is calculated
In short: This tool makes audio files louder without distortion. It measures loudness according to the international standard ITU-R BS.1770 (in LUFS), boosts to a target such as −14 LUFS for music streaming or −16 LUFS for podcasts, and catches peaks with a limiter before they clip. Everything runs in your browser.
How it works
- Drag in an audio or video file. Loudness, peak level and true peak are measured.
- Choose a method: normalize to loudness (LUFS), normalize to a peak level, or boost by a fixed number of decibels.
- Keep clipping protection on – it holds peaks below −1 dBFS.
- Click “Make louder & save”, listen and download (MP3 or WAV).
Background: loudness, peak level and clipping
How loud something sounds depends not on its loudest moment but on the average – weighted like human hearing. ITU-R BS.1770 defines a filter (K-weighting), 400-millisecond blocks and two gates that exclude silence and quiet pauses; the result is called integrated loudness, in LUFS. Broadcasting uses −23 LUFS (EBU R 128), Spotify normalizes music to −14 LUFS, and Apple Podcasts recommends −16 LUFS. The peak level (dBFS), by contrast, shows the single loudest sample; above 0 dBFS the signal is cut off – it “clips” and sounds distorted. That’s why a limiter with 5 ms look-ahead works here: it lowers the gain smoothly just before a peak and releases it afterwards.
The measurement was checked against the EBU Tech 3341 test signals (a stereo 1 kHz sine at −23 dBFS reads −23.0 LUFS).
Honest limits
- Very quiet recordings get louder – and so does their noise. A limiter is no substitute for mixing: if a lot of gain is needed, the result sounds denser and less dynamic.
- True peak is estimated with 4× oversampling; the limiter caps the samples, so the real peak after MP3 encoding can be a fraction of a decibel higher – −1 dBFS leaves headroom for that.
- MP3 is re-encoded. Files up to 30 minutes; long files need a lot of memory and a few seconds of processing.
Privacy
Your file is processed only in your browser and is never uploaded.
Frequently asked questions
How do I make an MP3 louder?
Drop the file here, choose e.g. “−14 LUFS” and click “Make louder & save”. Free, no software and no upload.
How do I make audio louder without distortion?
Keep clipping protection on. The limiter holds peaks below −1 dBFS while the rest of the signal gets louder.
What does LUFS mean?
LUFS (Loudness Units relative to Full Scale) measures perceived loudness according to ITU-R BS.1770. A difference of 1 LU equals 1 dB.
What loudness should podcasts and music have?
Apple recommends −16 LUFS for podcasts, Spotify normalizes music to −14 LUFS, and broadcasting uses −23 LUFS under EBU R 128. What counts are the specs of the platform you publish on.
Can I make the audio of a video louder?
You can open videos here – the soundtrack is read and boosted. Only the audio is saved (MP3 or WAV), not the video itself.
What’s the difference between normalizing and boosting?
When normalizing you set a target (e.g. −14 LUFS) and the tool works out the gain. When boosting you choose the decibels yourself.
Sources and legal basis
- ITU-R BS.1770 – Algorithms to measure audio programme loudness and true-peak audio level
- EBU R 128 – Loudness normalisation and permitted maximum level (−23 LUFS, −1 dBTP)
- EBU Tech 3341 – Loudness Metering: “EBU Mode” (test signals)
- Spotify for Artists – Loudness normalization (−14 LUFS; true peak below −1 dB)
- Apple Podcasts – Audio requirements (−16 LKFS ±1 dB, true peak ≤ −1 dBFS)
- MDN – BaseAudioContext.decodeAudioData()
- MDN – Web audio codec guide
- LAME MP3 Encoder (LGPL)
- lamejs – JavaScript port of LAME (LGPL-3.0), fork @breezystack/lamejs
- Microsoft/IBM – Multimedia Programming Interface and Data Specifications 1.0 (RIFF WAVE)
- Open-source licenses of the libraries used (MIT, LGPL-3.0)
As of:
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