Free Online Audio Volume Booster
Increase audio volume with gain control and clipping protection.
Load a file to measure its peak level and see how much headroom is available.
100% leaves the audio unchanged. 400% adds roughly 12 dB of gain.
The limiter rounds off peaks above 90% instead of letting them distort.
Boosting cannot recover detail that was recorded too quietly, and it raises background noise along with the voice. The limiter avoids harsh distortion but cannot create missing headroom.
Boosted audio
ReadyAbout the Audio Volume Booster
Quiet recordings are a common problem. A phone placed too far from a speaker, a lecture captured from the back of a room, or an interview recorded with conservative levels can all end up difficult to hear on a laptop or in a car. This tool raises the level of an audio file by up to four times, previews the result, and exports an MP3 or WAV copy. Decoding and processing happen in your browser with the Web Audio API, so the file is never uploaded.
Gain and decibels
The slider works in percent rather than decibels because percentages are easier to reason about. 200% doubles the amplitude, which is about +6 dB. 400% quadruples it, which is about +12 dB. Doubling the level does not double perceived loudness, since hearing responds logarithmically, but it is usually enough to make a quiet voice comfortably audible. The peak readouts show the actual sample maximum in dBFS, where 0 dBFS is the absolute limit of a digital file.
Clipping and the limiter
If the boosted peak would exceed 0 dBFS, the waveform is cut off at the top and bottom, which sounds like harsh crackle. The soft limiter avoids that by compressing peaks above 90% toward the ceiling instead of clipping them. It is not a full mastering compressor, but it keeps the result usable. Turning the limiter off gives a more aggressive, distorted sound and is only advisable when the input has lots of unused headroom.
Output choices
MP3 is the compact choice for sharing and playback. Bitrate affects size: 128 kbps is fine for speech, 192 kbps is a good general default, and 320 kbps keeps more detail for music. WAV stores uncompressed 16-bit PCM, which is larger but avoids another generation of lossy encoding. Both exports preserve the original duration and channel layout, with at most two channels retained.
Frequently asked questions
Can boosting make background noise worse?
Yes. Gain raises everything in the recording, including hiss, hum, and room noise. If the noise is already noticeable, reduce it before boosting rather than after.
Why does the peak stop below 100% when the limiter is on?
The limiter compresses only the loudest peaks, so the overall level rises while the maximum is held just under the ceiling. This is intentional and prevents digital clipping.
Will 400% always make the file loud enough?
Not necessarily. A very quiet source may need more than the maximum gain, while a recording with a single loud cough may already hit the limiter at 150%. Check the peak readout before exporting.