Increase audio volume
Quiet recordings made louder and even, without clipping.
Drop files here
or click to choose from your deviceAccepted: MP3, M4A, AAC, WAV, OGG, OGA, OPUS, FLAC, WEBA
Up to 3 files per runUp to 150 MB per file5 runs per dayRemove limits with Pro✓ Works offline
Your files stay on your device
This tool runs entirely in your browser. Nothing is uploaded, nothing is stored, and you can even turn off your internet connection before you start.
Example
Example: a lecture recorded on a phone, brought up to podcast level
A 50-minute lecture recorded from the back of the room, lecture.mp3, with the speech at about −31 dB. Volume: Automatic; Save as: Same as the original; Bit rate: 192 kbps.
- Automatic measures how loud the recording is in 0.4-second blocks, leaving out silence and pauses far below the rest: about −31 dB here.
- It brings that to the target of about −16 dB: +15 dB, the sound multiplied about 5.6 times.
- Where a laugh or a cough would go past the top, the limiter holds that moment just under −1 dB instead of letting it crackle.
| Measured loudness | Automatic changes it by | Sound multiplied by |
|---|---|---|
| −42 dB | +24 dB, the most it adds (ends near −18 dB) | 15.85 × |
| −31 dB | +15 dB | 5.62 × |
| −26 dB | +10 dB | 3.16 × |
| −20 dB | +4 dB | 1.58 × |
| −10 dB | −6 dB, made quieter | 0.5 × |
lecture-volume.mp3, an MP3 at 192 kbps with the voice at the level podcasts aim at and no clipped peaks. Any hiss in the room comes up with it; use Remove background noise first if it bothers you.
How it works
- Drop one or more audio files onto the box: MP3, M4A, WAV, OGG, FLAC and others.
- Leave the volume on Automatic to make the recording evenly and clearly audible, or choose how much louder (or quieter) it should be.
- Keep the original format or choose another, with its bit rate.
- Select Change volume and download the result.
Frequently asked questions
- Why does it not crackle when I make it much louder?
- Because the peaks go through a limiter. Simply multiplying the sound pushes the loudest moments past the maximum a file can hold, and they are cut off flat — that is the crackle. Here each tiny slice of the sound gets only as much gain as keeps it under the ceiling, so quiet passages get the full boost and the loud ones are held just below the limit.
- What does Automatic do?
- It measures how loud the recording is, leaving silence out, and brings it to about the level podcasts and phone speakers aim at. A very quiet recording can be raised by up to 24 dB; one that is already loud is lowered a little.
- Does it lower the quality?
- The sound is decoded and encoded again: MP3 and M4A at the bit rate you choose, WAV exactly. Raising the volume also raises any background noise in the recording; for that, use Remove background noise first.
- How much louder is +6 dB?
- +6 dB doubles the size of the sound wave (×2.0), +10 dB multiplies it by about 3.2 and +15 dB by about 5.6; −6 dB halves it. To the ear, +10 dB sounds roughly twice as loud.
- Does an MP3 stay an MP3?
- Yes, with Save as on Same as the original: an MP3 comes back as an MP3, an M4A as an M4A and a WAV as a WAV, named after the original with -volume added. Other formats, such as OGG or FLAC, come back as MP3. MP3 and M4A use the bit rate chosen, 192 kbps unless you pick another.
- Is my file uploaded, and what are the free limits?
- Nothing is uploaded. The free plan allows 3 files of up to 150 MB per run and 5 runs a day. Pro removes these limits.