Audio volume booster
Choose an audio file, set how many decibels louder or quieter, and save it. It runs in your browser and nothing is uploaded.
Free · no signup Runs in your browser
How do I make an audio file louder?
Choose the file, move the slider to the number of decibels you want to add (+6 dB is about twice the amplitude, +10 dB roughly twice as loud to the ear) and press Save. The tool multiplies every sample by the matching gain and saves MP3 or WAV. If the louder sound goes beyond the maximum, it is clipped, which sounds distorted, so add only as much as the recording can take.
Louder, but not too loud
A quiet recording from a phone or a far-away microphone is often fine except for its level. Raising the volume brings it to a normal listening level. Volume is measured in decibels (dB), a logarithmic scale: adding 6 dB doubles the amplitude of the waveform, adding 20 dB makes it ten times as large, and our ears hear about 10 dB as twice as loud.
The catch is a hard ceiling. A digital recording cannot go above full scale, so if the loudest parts already come close to it, a big boost pushes them over the edge and they are cut off flat. That is clipping, and it sounds like crackling distortion. The tool applies the gain to every sample and clips anything beyond full scale, and it cannot make a recording with sudden loud peaks and a very quiet background even; for that you need a compressor. For a recording that is simply quiet all through, a boost of 6 to 12 dB is usually safe.
It runs in your browser. Your file is never uploaded, and there is no watermark or sign-up. MP3 encoding uses LAME (lame.sourceforge.io), an open-source encoder, licensed under the LGPL.
When to use it
- Bringing a quiet voice memo or interview up to a normal level
- Making several recordings a similar loudness
- Turning a too-loud file down
- Checking how a recording sounds louder
Mistakes it helps you avoid
- Boosting so far that loud peaks clip and distort.
- Expecting it to even out loud and quiet parts: a boost changes everything equally.
- Boosting background noise along with the voice.
- Saving to MP3 repeatedly: keep your original.
How it works
Your audio is decoded, changed and saved inside your browser.
gain = 10 ^ (dB ÷ 20)+6 dB = ×2.0 amplitude +10 dB = ×3.16 +20 dB = ×10 −6 dB = ×0.5every sample is multiplied by the gain; values above full scale (1.0) are clippedthe result is written as WAV by hand or encoded as MP3 with LAME
Decibels measure ratios: +20 dB is ten times the amplitude and ten times the sound-pressure level, about four times as loud as it sounds to a listener. The tool applies a single gain to the whole file, so it does not normalise or compress. Clipping is hard (the wave is flattened at full scale). The range is −20 dB to +20 dB.
Example: a quiet voice memo
A voice memo peaks at about a quarter of full scale (−12 dB). You add 9 dB.
- Gain10 ^ (9 ÷ 20) = 2.82
- New peak0.25 × 2.82 = 0.71, below full scale
A clearly louder memo with no clipping
+12 dB would have taken the peak to 1.0, right at the limit.
Terms on this page
- Decibel (dB)
- A logarithmic unit for comparing levels; +6 dB doubles the amplitude.
- Clipping
- Distortion when a sound is pushed past the maximum and its peaks are flattened.
Common questions
What does +6 dB mean?
It doubles the amplitude of the sound wave. To the ear it is a modest increase in loudness.
Why does the sound crackle after boosting?
The louder peaks went past the maximum and were clipped. Lower the boost.
Can it make quiet and loud parts the same level?
No. A boost changes everything by the same amount. Evening out the level needs a compressor.
Is my audio uploaded?
No. Your browser reads and changes the sound on your own device. Nothing is sent over the network.
Can I make it quieter?
Yes. Use a negative number of decibels.
What to work out next
Where these numbers come from
- MDN Web Docs — GainNode and decibels How a change in volume is applied as a multiplication of the samples.
- MDN Web Docs — BaseAudioContext.decodeAudioData() How a browser decodes an audio file into samples.
- LAME MP3 encoder (lame.sourceforge.io), LGPL The MP3 encoder, here a JavaScript port (lamejs) used unmodified as a separate file.
- MDN Web Docs — Using files from web applications How a page reads a file you choose without uploading it.
Last verified 2026-10-25 The method on this page is checked against the sources above at least once a year. Spotted something out of date? Tell us and we will fix it.
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