Boost Audio
Boost and increase audio volume
Click or drop an audio file hereChoose an audio file
About Boost Audio
Boost Audio changes the volume of one audio file. Move the slider from 0.25× (quieter) to 5× (louder), or check "Normalize instead" to bring the whole file to an even loudness of -16 LUFS with true peaks at -1.5 dB. When you boost above 1× with "Prevent distortion" checked, as it is by default, a limiter holds the peaks just under full scale instead of cutting them flat. You choose among 18 output formats, from MP3 to FLAC and M4R. The gain is applied by ffmpeg.wasm on this page; an Opus result is the one case encoded on our server.
How to boost or normalize the volume of an audio file
- 1Pick or drop the recording that sounds too quiet or too loud.
- 2Set "Volume boost" with the slider, or check "Normalize instead" to aim at -16 LUFS.
- 3Leave "Prevent distortion" checked to keep loud peaks under full scale, or uncheck it for the raw gain.
- 4Choose the "Output format", then click "Boost audio".
- 5Listen to the result and click "Download" to save it as boosted_ followed by your file name.
Formats and limits
- Input formats
- MP3, WAV, M4A, AAC, FLAC, OGG, OGA, Opus, WMA, AC3, AIFF, AIF, AMR, MKA, WEBA, CAF, MP2, M4B, M4R, WV, AU
- Output formats
- MP3, WAV, AAC, FLAC, OGG (Vorbis), M4A, Opus, WMA, AIFF, ALAC, AC3, M4R, M4B, MP2, WV (WavPack), CAF, AU, MKA
- Volume
- 0.25× to 5× in steps of 0.25×, or loudness normalization to -16 LUFS (true peak -1.5 dB)
- Maximum file size
- 750 MB on a computer, 300 MB on a phone or tablet: the whole file is held in the browser tab's memory, and a larger one is refused as soon as you choose it. For Opus, the lossless FLAC sent to our server must also fit its maximum size and length.
- Usage limits
- Opus output counts toward an hourly and a daily number of jobs per connection on our server.
Where your file is processed
ffmpeg.wasm, downloaded from unpkg.com the first time, applies the gain to your file in your browser, except when you choose Opus. Then the boosted audio is rendered here as lossless FLAC, sent to our server, and encoded with libopus; the service erases that FLAC when encoding ends and the Opus file once your browser has fetched it, or after 15 minutes. A failed boost is reported to us with its cleaned message, the file extension and size range, and your browser's name and version.
Frequently asked questions
Will boosting make the audio distort?
No, not with the default settings. With "Prevent distortion" checked and a boost above 1×, the limiter turns down only the peaks that would pass full scale, so they are not cut flat; strong boosts then sound more compressed. Uncheck it to get the raw gain, clipping included.
Does "Normalize instead" make every file equally loud?
Yes, it aims at the same target: the loudnorm filter brings the file to -16 LUFS with true peaks at -1.5 dB, at the source sample rate (an Opus result takes a rate the Opus encoder supports, which can differ from the source). The slider is then disabled and the limiter box is ignored. A plain boost multiplies every sample by one factor instead.
Can I make a file quieter?
Yes. Move the slider below 1×, down to 0.25×. The limiter is not used there, since lowering the volume cannot push peaks past full scale. The file is still re-encoded into the output format you pick.
Will I lose quality if I keep the same format?
Yes, if that format is lossy. Changing the volume always means encoding again, so an MP3 saved as MP3 is compressed a second time. FLAC or ALAC add no further loss; WAV and AIFF are written in 16 bits, so a higher-resolution source loses depth.
Does boosting to Opus use a server?
Yes, Opus is the only output that does: the boosted audio goes to our server as FLAC and is encoded there with libopus. Each Opus boost counts as one job in your connection's hourly and daily allowance there. Every other format is boosted and saved in this tab by ffmpeg.wasm.
Tips and tricks
- ✓For voice memos recorded at different levels, try "Normalize instead" before the slider.
- ✓To boost only one passage, cut it out first with Trim Audio.