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Make audio louder

Boost a quiet recording, turn down a loud one, or even out a batch. Done on this device, never uploaded.

Makes an MP3, voice memo or video louder or quieter, or normalizes a batch to the same loudness. It is free, needs no account and adds no watermark, and your files are not uploaded: everything runs in your browser on your device. The size limit is your device’s memory, and phones hold less; give the page a short while after your first run to save itself for offline use, and then it works offline.

Drop audio or video files to change the volumeor click to choose files. Batches welcome.

    Peaks that would clip are gently turned down, so nothing distorts.

    Videos keep their picture untouched and get the new sound.

    Working…

    Done

    Your files are processed on this device and never sent to a server. Reload the page to clear everything from memory.

    How it works

    1. Drop one or more sound files (MP3, WAV, M4A, FLAC, OGG) or videos (MP4, MOV, WebM), or tap to pick them.
    2. Choose how much louder or quieter, or Normalize to bring every file to the same comfortable loudness. Keep the original format or pick another.
    3. Run it. Peaks that would clip are eased down so nothing distorts. Videos keep their picture untouched and get the new sound.

    In your browser, not on a server

    Your browser decodes the sound with its own audio decoders. Every sample is multiplied by the gain you chose (or the gain that brings the gated loudness to about −14 LUFS), then a look-ahead peak limiter turns down only the moments that would pass −1 dBFS, easing in over 5 ms and out over 150 ms. The file is written again in your tab: MP3 by LAME in WebAssembly, WAV and FLAC by code in this site, M4A and OGG by the browser’s own encoders. For a video, Mediabunny (MPL-2.0) copies the picture packets unchanged and adds the new sound.

    Compared with upload-based tools: Online volume boosters upload the recording or video, cap the file size, and often just multiply the samples so loud parts clip and crackle. Here nothing leaves your device and the limiter keeps boosted sound clean.

    Verify it yourself. Give the page a short while after your first run to save itself for offline use, then turn off Wi-Fi or switch to airplane mode and run the tool again. Or open your browser's developer tools (F12, or Cmd-Option-I on a Mac), pick the Network tab, and watch it while you convert. The panel above does the same count for you.

    Questions

    Are my files uploaded?

    No. Your browser decodes the sound, the volume change runs in the page, and the file is written again in your tab. Videos have their picture copied across without re-encoding. Your files are not uploaded, and it works offline after your first run.

    Will boosting make it distort?

    Not by clipping. A limiter looks a few milliseconds ahead and turns down only the peaks that would go past the top, then eases back, so a +10 dB boost stays clean. The result card says what share of the sound was eased. Very large boosts on already loud music will sound squashed; use Normalize for those.

    What does Normalize do?

    It measures how loud the talking or music is (ignoring pauses) and turns each file up or down to about −14 LUFS, the level Spotify and YouTube play at. A batch of voice memos or podcast clips ends up at the same volume.

    Does it make a video louder too?

    Yes. Drop an MP4, MOV or WebM and the new sound is put back with the original picture, which is copied as it is. The sound is re-encoded as AAC in an MP4, or Opus in a WebM.

    Does the MP3 lose quality?

    Saving an MP3 again re-encodes it, at about the original’s bitrate, which is inaudible for most listening. For editing, save as WAV or FLAC.

    More video and audio tools

    Remove background noise

    Keep the voice, lose the hiss, hum and fan noise. Cleaned on this device, never uploaded.

    Merge audio

    Combine songs, voice notes or podcast segments into one file. Done on this device, never uploaded.

    Mic test

    Check that your microphone works before a Zoom, Teams or Discord call: speak and watch the level, then play back five seconds to hear how you sound. Nothing is uploaded.

    Webcam test

    Check that your webcam works before a Zoom, Teams or interview call: see the live picture, the real resolution and the measured frame rate. Nothing is uploaded.

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