Free Audio Loudness Normalizer (LUFS)
Measure your audio's loudness to the ITU-R BS.1770 standard (LUFS) and normalize it to a streaming, podcast, or broadcast target — with a true-peak ceiling so it never clips. Decodes MP3/WAV/M4A/OGG/FLAC and exports WAV, FLAC, MP3, M4A or OGG, all in your browser.
Many audio sites upload your file before they process it — here it's normalized on your device.
Drop files here, or click to browse
MP3, WAV, M4A, OGG, FLAC, AAC, MP4, M4V, MOV, WEBM, MKV · processed on your device
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Your files never leave your device. All processing happens locally in your browser.
Proper loudness measurement. Integrated loudness is computed to the ITU-R BS.1770 standard — K-weighting filter, 400 ms blocks with overlap, and absolute (−70) + relative (−10 LU) gating, measured at 48 kHz. Gain is then applied to reach your target, with a −1 dBFS peak ceiling so the result never clips.
Export as lossless 16-bit WAV, FLAC, or as MP3, M4A or OGG at the bitrate you pick. Video files keep their picture and get the normalized sound. Decoding and processing happen entirely in your browser; nothing is uploaded.
Common uses
- Normalize Podcast Audio to −16 LUFSMatch the loudness target Apple Podcasts expects, so your episode sits level with every other show in the feed.
- Normalize Music to −14 LUFS for Spotify and YouTubeHit the loudness the streaming platforms normalize to, instead of letting them turn your master down for you.
- Normalize to −23 LUFS for EBU R128 BroadcastMeet the European broadcast loudness standard for TV, radio, and festival or station deliverables.
- Normalize Audiobook Narration for ACXGet narration into the loudness window Audible/ACX submissions are checked against.
How It Works
Measures your audio's integrated loudness to the broadcast-standard ITU-R BS.1770 (the same LUFS scale streaming platforms use) and applies gain to hit a target, with peak protection so it never clips. Exports WAV, FLAC, MP3, M4A or OGG.
- 1Drop an audio fileMP3, WAV, M4A, OGG, or FLAC. It is decoded in your browser; nothing is uploaded.
- 2Loudness is measured properlyA K-weighting filter, 400 ms gated blocks, and absolute + relative gating (measured at 48 kHz) give a true integrated-LUFS reading — not a crude peak or RMS.
- 3Pick a target and downloadChoose −14 (streaming), −16 (Apple/podcast), −23 (broadcast), or −9 (loud). Gain is applied to hit it, and a true-peak limiter keeps the peaks under the ceiling (−1 dBTP by default) so the result never clips. Download it in the format you picked.
Decoding and processing run entirely in your browser. Your audio is never uploaded.
Guide
Worked example
A 20-minute mono interview measures -24.0 LUFS with a true peak of -6 dBTP. Choosing "Apple Music / Podcasts -16" needs +8 dB of gain, which would push the loudest peak 2 dB over full scale. With the "True-peak limiter" on (the default), the tool turns only the loudest peaks down by about 3.5 dB to stay under the -1 dBTP ceiling, so the result lands at about -16 LUFS without clipping. Exported as MP3 at the default 192 kbps, 20 minutes is about 29 MB.
Which settings to use, and the limits
- Choose the preset your platform asks for. Each preset sets a loudness target and a true-peak ceiling together: -14 LUFS streaming and social, -16 Apple, -19 mono podcast, -20 ACX with a -3 dBTP ceiling, -23 EBU R128 and -24 US TV. After processing, the tool says whether the result meets that spec.
- Use the speech leveller for uneven voices. Normalizing moves the average and cannot make a quiet speaker louder than a loud one. "Gentle" or "Strong" under "Speech leveller" evens out passages first. It is meant for interviews and phone memos, not for music.
- Watch the limiter cap. If a file would need more than 12 dB of limiting to reach the target, the tool stops at 12 dB and the result ends a little below the target, because more would sound squashed. A quieter target or a cleaner source is the better fix.
- Pick WAV or FLAC to stay lossless. The output starts in your file's own format (MP3 in, MP3 out; WAV for video and other inputs). MP3, M4A and OGG are offered at 96, 128, 192, 256 or 320 kbps. For a video the picture is copied untouched and only the sound is replaced.
- Mind file size. The whole file is decoded to memory for measuring, so there is a size limit by device: about 2 GB on a computer, 1 GB on low-memory computers and 400 MB on a phone. An hour of 44.1 kHz stereo audio is more than 1 GB once decoded.
Common problems and how to fix them
- It says it could not decode this audio file.
- The file may be damaged or in a format this browser cannot decode. Try MP3, WAV, M4A, OGG or FLAC. If the message also mentions size, the file is too long to decode on this device, so trim it first.
- A video file could not be read.
- The video may have no audio track, or use a sound format the browser cannot decode. Check that it plays with sound, or extract the audio with the Audio Extractor first.
- The file is refused as too large.
- The message shows your file size and the limit for this device. Trim to a shorter section, or use a desktop computer, which allows larger files than a phone.
- The result is a little quieter than the target.
- The tool will not clip. If the limiter is off, gain is held so the true peak stays under the ceiling. If it is on, the 12 dB cap applies. A note under the readout says which. Use a lower target, a higher ceiling such as -0.5 dBTP, or the speech leveller.
How it compares
Peak normalization sets the loudest sample to a level, which says little about how loud a file sounds. Loudness normalization, used here, measures integrated loudness in LUFS (ITU-R BS.1770) and moves the whole file to a target, which is what streaming and broadcast specs are written in. The trade-off is that a dynamic recording may need peak limiting to reach a loud target.
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