About the Volume Booster
Make a quiet recording louder, or bring down one that is too loud. Choose the file, set the change in decibels, such as +6 dB, and download the result. A quiet voice note, a lecture recorded from the back of the room, or a song that plays softer than the rest of your playlist can all be fixed in a few seconds.
A limiter is on by default so the boosted sound doesn't distort. Everything happens in your browser; nothing is uploaded, and files up to 100 MB work, including the sound of videos.
How it works
Every sample is multiplied by the same amount: 10 to the power of the decibels divided by 20. +6 dB is about twice the level, +12 dB about four times, and −6 dB about half. Before the change, the tool measures the loudest point of the file and shows it with the result.
Digital audio can't go above full scale (0 dB). Boosting a file whose loudest point is −3 dB by 6 dB would push the peaks to +3 dB, and they would be cut flat, which sounds harsh. With Prevent distortion on, a limiter holds those peaks just below full scale at −1 dB, while everything quieter gets the full boost.
Turn the limiter off only if you want an exact multiplication of every sample and know the peaks have room. Lowering the volume never needs the limiter.
Assumptions and limits
- The change can be from −30 dB to +30 dB, in any step such as 4.5 dB.
- MP3, M4A and OGG are saved at 192 kbps; WAV and FLAC keep every detail.
- To make several files equally loud, a loudness normaliser is the better tool; this one changes the level by a fixed amount.
Worked examples
A quiet voice note
A recording peaking at −18 dB can take a +12 dB boost with no limiting at all, reaching −6 dB.
A loud song made louder
A song peaking at −1 dB boosted by +6 dB has its peaks held at −1 dB by the limiter while the quieter parts rise by the full 6 dB.
Turning a track down
−6 dB halves every sample, which is useful for background music under a voice-over.
How to use the Volume Booster
- Choose the quiet file. Audio or a video, up to 100 MB.
- Set the boost in dB. +6 dB is about twice as loud in level.
- Save the louder file. Peaks are kept below distortion.
Frequently asked questions
How do I make an MP3 louder?
Choose the MP3, set a boost such as +6 dB, leave Prevent distortion on, and press Boost the volume. The louder MP3 is made in your browser in seconds, without uploading the file or installing an app.
How many decibels should I boost?
Start with +6 dB, which doubles the level. If the result still sounds quiet, try +10 or +12 dB. The result shows the file's loudest point before the change, so you can see how much room there was.
Why does boosting sometimes make audio distort?
Digital audio has a ceiling at full scale. If a boost pushes the loudest peaks above it, they are clipped flat, which sounds crackly. The limiter here holds peaks just below the ceiling so the rest of the sound can still get louder.
Can I make a video's sound louder?
You can choose a video here and get its sound back as a louder audio file, such as an MP3. The picture isn't kept; to keep the video, a video volume tool is needed.
Is the volume change exact?
Yes. Every sample is multiplied by exactly 10^(dB/20), so +6 dB makes the level 1.995 times larger. Only peaks that would go over −1 dB are reduced by the limiter, and only while it is turned on.
This tool runs entirely in your browser. What you enter or upload stays on your device and is never sent to our servers.