Volume Booster
Fix a recording that's too quiet: raise the volume of an MP3, voice memo or video by up to 20 dB with a limiter that stops distortion, or let it even out the loudness automatically. Free, no watermark, and your file stays on your device.
Free · No sign-upHow to use Volume Booster
- 1. Drop an audio or video file (MP3, M4A, WAV, MP4, MOV, MKV, WebM…). The tool measures its loudest peak and average level.
- 2. Choose Boost + limiter and set the gain (−20 to +20 dB), or pick Auto: even out for speech, or Auto: loudness target (−14, −16 or −23 LUFS).
- 3. Press 🎧 Preview louder to hear an approximate boost in real time, and switch back to the original to compare.
- 4. Click Boost & save. The result shows the peak and average level before and after — then Download it. Videos keep the same picture; only the sound is re-encoded.
Frequently asked questions
Will boosting the volume distort the sound?
Not with Boost + limiter: a look-ahead limiter holds the peaks just under full scale (about −1 dBFS or lower), so there's no hard clipping even at +20 dB. Very large boosts do make the sound more compressed and also raise background noise, so use the smallest gain that works — the tool shows the maximum boost possible without any limiting.
What's the difference between the three modes?
Boost + limiter applies your exact gain. Auto: even out uses a dynamic normalizer that lifts quiet passages and tames loud ones — good for lectures, calls and interviews. Auto: loudness target measures loudness the EBU R128 way and normalizes it to −14, −16 or −23 LUFS, the levels used by streaming services, podcasts and broadcast.
Does it change the video?
No. For MP4, MOV, M4V, MKV and WebM files the video stream is copied bit for bit and only the audio is re-encoded (AAC, or Vorbis for WebM). Other video formats such as AVI or WMV are saved as MP4; if their video codec doesn't fit MP4 it is re-encoded to H.264.
Is my file uploaded?
No. Measuring and boosting run in your browser with ffmpeg compiled to WebAssembly, downloaded once (about 32 MB) and then cached. Nothing is sent to a server.
Can I make audio quieter too?
Yes. Drag the gain below 0 dB (down to −20 dB) to lower the volume. Everything else works the same.
Which formats are supported?
Most audio and video files: MP3, M4A/AAC, WAV, FLAC, OGG, Opus, WMA, MP4, MOV, MKV, WebM, AVI and more. Audio can be saved as MP3, M4A or WAV; only the first audio track is processed, and embedded cover art isn't kept.