Audio Volume Booster and Normalizer
Make quiet audio louder or normalize it to a target level in your browser, with no upload.
- Runs in your browser, files never leave your device
- Free, open source, no account, no ads
- Works offline after the first visit
Audio Volume Booster and Normalizer
Drop an audio file here or choose a file
MP3, WAV, M4A, OGG, FLAC and more. Nothing is uploaded.
Your recording stays on this device. The file is decoded, measured and re-encoded by your browser. No server ever receives it, so it is safe for private calls, interviews and voice notes.
Original After gain Clipping
- Duration
- –
- Peak level
- –
- Loudness (RMS)
- –
How it works
- Open a recording. Drop an MP3, WAV, M4A or other audio file. Your browser decodes it and measures the peak level and average loudness (RMS) in decibels.
- Boost or normalize. Drag the gain slider, or let the tool compute the gain for a peak or RMS target. Play the preview and flip between before and after; turn on Prevent clipping if peaks would distort.
- Save it. The louder file is rendered on your device as MP3 or WAV with the same sample rate, and the real peak and loudness of the result are measured and shown.
Questions, answered
Are my files uploaded anywhere?
No. Audio Volume Booster and Normalizer runs entirely in your browser. Your files are read into memory on your device, processed with JavaScript, and never sent to a server. You can disconnect from the internet and it keeps working.
What is the difference between Boost and Normalize?
Boost applies the exact gain you pick, from −20 to +30 dB. Normalize measures the file and picks the gain for you: a peak target (default −1 dBFS) makes the loudest moment hit that level, an RMS target (default −16 dB) matches the average loudness, which is closer to how loud it sounds but may need the limiter to avoid clipping.
Can it fix a recording that is already distorted?
No. If the original was recorded too hot, the tops of the waveform are cut flat and that information is gone. The tool warns you when it detects this. Prevent clipping only protects new peaks created by the boost, using a soft tanh-style limiter that keeps everything below −0.5 dBFS.
Is it really free?
Yes. It is open source under the MIT license, with no account, no length limits, no watermark and no ads. If it saves you a paid subscription, you can say thanks on Ko-fi.
Does it work offline?
Yes. After your first visit the page is cached by a service worker, so it loads without a connection. You can also install it from your browser's menu as an app. Very long files (more than about an hour) need a lot of memory, so a phone may struggle with them.
Was this written by AI?
Yes. Audio Volume Booster and Normalizer was generated by Claude Code from a written specification inside an automated pipeline, with a test suite that runs in a real browser. The full source is on GitHub, so you can read every line before you trust it with your files.
Built by one person, given away for free
Audio Volume Booster and Normalizer is a free alternative to paid tools like Online MP3 volume booster and louder tools such as Clideo Change Volume and 123apps Volume Changer. If it earns a place in your bookmarks, a coffee keeps the updates coming.
☕ Support Or on Ko-fi