About this tool
Fix a recording that came out too quiet, tame one that is too loud, or bring a set of files to the same level. Enter a change in decibels, or tick normalise to have the loudness measured and set to the standard -16 LUFS used for podcasts and streaming, which also prevents clipping.
Everything happens inside your browser. Your file is never uploaded to a server: the conversion runs on your own device using WebAssembly, and the result is downloaded straight from memory. Close the tab and nothing is left behind.
How to use it
- Drop your MP3 files into the box above, or click to browse. Nothing is uploaded.
- Adjust the options if you want; the defaults suit most files.
- Click the button and wait a moment.
- Download the results individually or all at once as a ZIP.
Frequently asked questions
What does normalise do?
It analyses the whole file and adjusts it to a target loudness with peaks limited to -1.5 dB, so nothing distorts. Use it when files should sound equally loud.
Why does my boosted audio sound distorted?
You pushed the peaks past full scale. Use a smaller boost or normalise instead.
Is this really free?
Yes. The site is supported by ads, and there are no limits on how many files you convert.
Are my files uploaded anywhere?
No. The converter runs entirely in your browser. Files stay on your device, which also makes it faster than upload-based converters for anything larger than a few megabytes.
Is there a file size limit?
The only limit is your device's memory. Images and audio of any normal size are fine; for video, files under about 500 MB work well on most laptops and phones.
Which browsers are supported?
Current versions of Chrome, Edge, Firefox, and Safari on desktop and mobile. Very old browsers without WebAssembly support will not work.