Change audio volume — free online tool
Change audio volume from 0 to 200 percent with a single multiplier; includes the decibel equivalents for 50, 150 and 200 percent.
What to know
The Volume slider runs from 0 to 200 percent in steps of 1 and is applied as a plain multiplier on every sample: 100 percent leaves the file as it is, 50 percent halves the amplitude, and 0 percent makes silence.
Percent and decibels line up through 20 times the base-10 logarithm of the multiplier. At 50 percent the change is about -6 dB, at 150 percent about +3.5 dB, at 200 percent about +6 dB and at 25 percent about -12 dB. A change of 3 dB is clearly audible, and 6 dB is generally heard as a jump.
Raising volume has a ceiling. A 16-bit file cannot go past full scale, so if the loudest peak is at 80 percent of full scale, a 150 percent boost pushes it to 120 percent and the top of the wave is flattened. That clipping sounds harsh and cannot be undone, so listen to the loudest passage in the preview.
The tool does not match loudness between files or normalize to a target. It multiplies by the number you set, which is the right behavior when you want exactly the same change applied to several clips of one session.
Tone is untouched. When a voice is quiet and also dull, run the Equalizer first and Volume afterwards.
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How to use Change audio volume — free online tool
- Load a quiet recording such as lecture.m4a.
- Drag the Volume slider to 150 percent and read the value shown beside it.
- Export as MP3 at 192 kbps or as WAV if you will keep editing.
- Process and check the loudest part in the preview for harsh, flat-topped distortion; if you hear any, return to about 120 percent.
Quick answers
How many decibels is 200 percent volume?
About +6 dB, from 20 x log10(2) = 6.02. The amplitude doubles.
Why does 150 percent sound distorted on my file?
The loudest peaks may have been pushed past full scale and clipped. Choose a lower percentage until the loudest passage stays clean.
Is 50 percent the same as half as loud?
It halves the amplitude, about -6 dB. Perceived loudness drops less sharply, since listeners judge a 10 dB cut as roughly half as loud.
Does the tool normalize to a loudness target?
No. It only multiplies the signal by the percentage you set.