How this volume booster works
Load an audio file and the tool scans every sample to find the current peak level in dBFS — a quiet phone recording often peaks around -20 dBFS, leaving plenty of headroom. Then pick a mode: Manual gain applies a fixed boost or cut from -12 to +24 dB, while Normalize to peak calculates the exact gain that lands the loudest moment on your chosen target (-1, -3 or -6 dBFS). The result is rendered to a new buffer, drawn as a waveform, playable right on the page and downloadable as WAV.
A live warning appears whenever the selected gain would push the peak past 0 dBFS, and after processing the tool reports exactly how many samples were clamped — zero is what you want.
Manual gain or normalize?
Normalize is the safe default: it makes the file as loud as possible without clipping, which is what most people mean by “make it louder.” -1 dBFS maximizes level; -3 dBFS leaves headroom for further editing or lossy re-encoding. Reach for manual gain when you need a specific change — matching two clips, taming an over-hot recording with negative gain, or deliberately pushing past the peak warning when only a brief transient clips and the body of the audio needs the lift.
Louder is not always better
Gain amplifies everything, including hiss and room noise — a whisper boosted 24 dB is a loud whisper over loud hiss. If the file has quiet and loud sections, consider trimming to the useful part first with the Audio Trimmer, then normalizing the remainder. Need a different container for the result? The Audio to WAV Converter covers resampling and mono mixdown.