An audio volume booster that will not distort
This audio volume booster makes a quiet recording louder and saves it as a new file. Use it for a lecture recorded from the back of the room, a phone voice note that is hard to hear in the car, a soft interview track, a song that plays too quietly next to the rest of your playlist, or a video soundtrack you have extracted. Choose how many decibels to add, check the clipping meter, preview and download.
Simply multiplying the samples makes the loudest moments go past the maximum a file can hold, which is heard as harsh crackle (clipping). Here a look-ahead true-peak limiter rides the gain down just before each peak and lets it back up smoothly afterwards, so the quiet parts get the full boost while the peaks stay below the ceiling you choose — including the peaks that form between samples when the file is played back.
Your file stays on your device. The boost, the limiter and the encoders all run in the browser tab, with a progress bar and a Cancel button for long files.
How to use the Audio Volume Booster
- Drop an audio file onto the box or click to choose one. The loudness (LUFS) and true peak (dBTP) of the original are measured and shown.
- Pick a quick boost such as +6 dB, drag the slider or type the Gain in decibels; the hint shows the same boost as a percentage.
- Read the clipping meter: it tells you how high the peaks would go and how much of the audio would clip. Keep the True-peak limiter on and choose a Peak ceiling (−1 dBTP suits almost everything).
- Press Preview to hear eight seconds from the marker on the waveform, and Original to compare.
- Choose the output format, press Boost volume, compare loudness before and after, and press Download.
Audio Volume Booster features
Boost by −30 to +40 dB
Quick buttons from +3 to +20 dB, a slider and an exact field in 0.5 dB steps; negative values make audio quieter.
True-peak limiter
Peaks are measured with 4× oversampling (as described in ITU-R BS.1770) and held under the ceiling with a 3 ms look-ahead and a smooth 150 ms release.
Clipping meter
Before you process, see the peak after the boost and the exact percentage of samples that would clip without the limiter.
Loudness before and after
Integrated loudness in LUFS and true peak in dBTP for the original and the result, plus how hard the limiter had to work.
Preview and waveform
Hear the boost on a short excerpt first; the result’s waveform shows the ceiling lines.
Save in any common format
MP3, M4A (AAC), WAV (16/24-bit or 32-bit float), FLAC or OGG Vorbis.
Decibels and percent
Every 6 dB doubles the amplitude of the signal. Perceived loudness grows more slowly: most people hear about +10 dB as “twice as loud”. The percentage shown in the tool is the amplitude, which is how most media players label their volume boost.
| Boost | Amplitude | How it sounds |
|---|---|---|
| +3 dB | 141 % | Slightly louder |
| +6 dB | 200 % | Clearly louder |
| +10 dB | 316 % | About twice as loud |
| +12 dB | 398 % | Much louder |
| +20 dB | 1000 % | About four times as loud — for very quiet recordings |
Why a limiter beats plain amplification
A digital file cannot store values above full scale (0 dBFS). Turn a recording up so its loudest syllable would reach +6 dBFS and those samples are flattened, producing distortion. Even if no sample reaches 0 dBFS, the smooth waveform a player reconstructs between samples can — these inter-sample or true peaks are why lossy files such as MP3 often clip after a careless boost.
The limiter works out, for every sample, how much the gain must drop to keep the oversampled peak under the ceiling, holds that reduction for the next 3 ms so it is already in place when the peak arrives, smooths it, and releases over about 150 ms. Only the loudest moments are touched, which keeps speech and music natural. If the meter says the limiter would take off more than 6–8 dB, the recording has strong peaks: a smaller boost, or loudness normalisation, may sound better.
Tips for very quiet recordings
- Boosting also raises background hiss and hum. Clean the recording with the Audio Noise Remover first, then boost.
- To make several files equally loud rather than adding a fixed amount, use the Audio Normalizer, which targets a loudness level such as −16 LUFS.
- For a lossy format, keep the ceiling at −1 dBTP or lower so the encoder has headroom.
- Recording something new? The Voice Recorder shows a live level meter so you can set the microphone level right from the start.
Audio Volume Booster FAQ
How do I increase the volume of an MP3 without distortion?
Open the MP3 in this audio volume booster, set the gain, keep the true-peak limiter on with a −1 dBTP ceiling and press Boost volume. The limiter stops the loudest moments from clipping while everything else gets louder.
How many decibels should I boost?
Look at the clipping meter: if the peak after the boost stays at or below the ceiling, nothing is limited. For speech, a result around −16 to −14 LUFS is comfortably loud on phones.
Is it free and private?
Yes. The volume booster is free with no sign-up or watermark, and your file is processed on your own device — it is never uploaded.
What is the difference between this and normalizing?
A booster adds the same amount of gain you choose. A normalizer measures the file and picks the gain for you so it reaches a target loudness or peak — handy when several files must match.
Why does the boosted file sound noisier?
The background noise was already there and has been made louder along with the voice. Remove noise first, then boost.
Can I make audio quieter?
Yes — type a negative gain such as −6 dB. The limiter is not needed then, but it does no harm.