Volume Booster
Make quiet recordings louder without distortion. Files never leave your device.
No upload · Processed in your browserMP3 · M4A · WAV · OGG · FLAC500 MB per file (recommended)As of 2026.10.01
Boosts less when needed so the peak stays at or below −1 dBFS
The peak is measured during processing
How to use Volume Booster
- 1Drag and drop one audio file or pick it with [Choose files]. Its loudest point (the peak) is measured as you add it
- 2Choose a Boost (+3, +6, +10 or +15 dB, or Normalize to max), check the “about n dBFS after” line below the options, then press [Start]
- 3Listen to the result, then save it with [Download]
The big number on the result card is the size of the result file, and you can listen to the result right there. The result also shows how much was actually boosted and how the peak changed, as in “Boosted by +6.0 dB” and “Peak −20.0 → −14.0 dBFS”. Each result keeps the original name with -louder added, as in lecture.m4a → lecture-louder.m4a, and keeps the original format; only FLAC is saved as WAV.
You can add one audio file at a time. We recommend up to 500 MB on desktop and 100 MB on mobile. Going over the recommendation shows a warning, but you can still continue. Files over 2 GB are not processed.
- Example 1 · +6 dB (default)
tone-10s.wav (10 s, peak −20 dBFS) · 1.8 MB · +6 dB · Prevent clipping on
Measured in Chrome on desktop · test audio (1 kHz tone, 48 kHz stereo) · on adding, the panel showed “Peak now −20.0 dBFS → about −14.0 dBFS after”
→ tone-10s-louder.wav · 1.8 MB · peak −14.0 dBFS
- Example 2 · Normalize to max
tone-10s.wav (peak −20 dBFS) · Normalize to max
Measured in Chrome on desktop · test audio (1 kHz tone)
→ Boosted by +19 dB · peak −1.0 dBFS
- Example 3 · +6 dB on an already loud file
tone-loud-10s.wav (peak −3 dBFS) · +6 dB · Prevent clipping on
Measured in Chrome on desktop · test audio (1 kHz tone)
→ Boosted only +2.0 dB · peak −1.0 dBFS · message “Boosted only +2.0 dB to prevent clipping”
- Example 4 · +6 dB on an MP3
tone-10s.mp3 (128kbps) · 157 KB · +6 dB
Measured in Chrome on desktop · test audio (1 kHz tone)
→ tone-10s-louder.mp3 · 236 KB · re-encoded as MP3 at 192kbps
Example figures vary by file and device.
Volume Booster options explained
- Boost
- Choose +3, +6 (default), +10 or +15 dB. The amplitude is multiplied by 10^(dB ÷ 20), so +3 dB is about 1.4×, +6 dB about 2×, +10 dB about 3.2× and +15 dB about 5.6×. If a lecture or meeting recording is a little quiet, try +6 dB; if it's very quiet, start at +10 dB. The whole file is multiplied by the same amount, so background noise gets louder by the same ratio.
- Normalize to max
- Works out the boost automatically so the loudest point (the peak) lands at −1 dBFS. If the peak is already above −1 dBFS, the file is turned down to match. This suits files when you don't know how quiet they are. With this choice, Prevent clipping isn't used, because the peak is already set to −1 dBFS.
- Prevent clipping
- On by default. If the boost you chose would push the peak above −1 dBFS, the file is boosted only up to that point and the result says “Boosted only +x dB to prevent clipping”. It never turns the sound down, so if the peak is already at −1 dBFS or higher, nothing is boosted and you'll see “The peak was already high, so the volume was not raised”. When it's off, the full boost is applied and anything above 0 dBFS is cut off (clipped), which can sound distorted.
- Peak display
- If this browser can decode the sound when you add the file, the peak is measured and shown below the options as “Peak now −n dBFS → about −m dBFS after”. If it can't, you'll see “The peak is measured during processing”; after you press [Start], it's measured while processing and the same rules apply. dBFS is a scale where 0 is the largest value digital audio can hold, so the closer to 0, the louder.
- Saved format
- This isn't a setting you can turn on or off; it always works the same way. The audio is re-encoded and saved in the same format as the original: MP3 at 192kbps, M4A as AAC at 192kbps, OGG as Opus at 128kbps, WAV as 16-bit, and FLAC as 16-bit WAV. Tags such as the title and other metadata are not carried over to the result.
Volume Booster: frequently asked questions
Are my audio files sent to a server?
No. The volume boost happens inside this browser and your files are never sent off your device. To check it yourself, follow the steps on the How it works page.
How many dB should I add?
Start by listening with the default, +6 dB. It roughly doubles the amplitude: our test file with a peak of −20 dBFS came out at −14.0 dBFS. If it's still quiet, try +10 or +15 dB, and if you're not sure how much to add, choose Normalize to max. The same test file with Normalize to max was boosted by +19 dB to a peak of −1.0 dBFS. The “about n dBFS after” line below the options shows the result in advance.
It didn't get as loud as I chose.
With Prevent clipping on, the boost stops where the peak would pass −1 dBFS. For a test file peaking at −3 dBFS, choosing +6 dB boosted only +2.0 dB to a peak of −1.0 dBFS, and the result said “Boosted only +2.0 dB to prevent clipping”. If a single loud sound, such as a clap or a cough, sets the peak, the rest can't be raised further even if it's quiet. If that sound is at the start or end, cut it off with Cut Audio first. Turning Prevent clipping off applies the full boost, but anything above 0 dBFS is clipped and may sound distorted.
Does boosting change the quality or file size?
The audio is re-encoded, so MP3, M4A and OGG go through lossy compression one more time. MP3 is saved at 192kbps: our 128kbps test file (157 KB) became 236 KB. WAV is saved as 16-bit, and the test file stayed 1.8 MB after boosting. Background noise gets louder by the same ratio, and there's no noise reduction.
It says “The peak is measured during processing”.
This browser couldn't decode the sound when you added the file, so the peak wasn't measured in advance. After you press [Start], the peak is measured while processing, the same rules are applied, and the result shows how much was actually boosted. Codecs this browser can't handle are processed with the fallback engine (FFmpeg), which is downloaded the first time while “Preparing the processing engine · about 31 MB, first time only” is shown.
Can I boost the sound of a video?
This tool only accepts MP3, M4A, WAV, OGG and FLAC audio files. To boost the sound from a video, pull it out first with Video to MP3, then add it here.
My call or lecture recording is too quiet.
Choose Normalize to max and the loudest sound in the file is raised to −1 dBFS, adding as much gain as that allows. It suits recordings where only the voice is quiet. If there’s a one-off loud sound such as a cough or a bump on the desk, the boost is limited by that peak, so cut that part out with Cut Audio first. Background noise gets louder by the same amount; there’s no noise reduction.
Related tools
How it works · Engine · Notes
- Processed in: this browser (your device)
- Engine: Mediabunny (MPL-2.0) · WebCodecs (built into the browser) (—) · LAME (Mediabunny MP3 encoder) (LGPL-2.0-or-later) · Mediabunny AAC encoder (LGPL-2.1-or-later) · FFmpeg (ffmpeg.wasm, fallback) (GPL-2.0-or-later)
- The volume boost runs inside this browser: Mediabunny decodes the audio, the gain is applied, and it's re-encoded with the browser's built-in codecs (WebCodecs) and encoders such as LAME (WebAssembly) for MP3. Files are not sent to a server.
- The gain is 10^(dB ÷ 20). With Prevent clipping on, the actual boost is the smaller of your choice and (−1 − peak) dB, and never below 0 dB.
- Codecs this browser can't handle are processed with a fallback engine (FFmpeg, WebAssembly, about 31 MB) that is downloaded the first time and kept in the browser cache.
- Tags such as the title and other metadata are not carried over to the result.
- As of 2026.10.01
- Changelog: 2026.10.01 First release