Audio Optimizer
Trim, compress and convert audio to MP3 or WAV — with a waveform editor, adjustable bitrate and a live size estimate. Everything stays in your browser.
0:00 / 0:00 Drag the handles to trim
Optimize for — sets bitrate & channels
Output settings
128 kbps
Selection
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Original
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Estimated output
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Saved
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Recommendation
Load an audio file to see a tailored suggestion.
Encoding…
100% private — your audio is processed locally and never uploaded to any server.
How to optimize audio
- Upload a file by dragging it onto the drop zone or clicking to browse. MP3, WAV, M4A, OGG and FLAC are supported.
- Trim it. Drag the handles on the waveform to keep just the part you want, and press play to preview the selection.
- Pick an "Optimize for" preset — Music, Podcast, Web background and more — to set the ideal bitrate and channels in one click, or adjust them manually.
- Choose a format (MP3 for the web, WAV for lossless) and watch the estimated output size update live.
- Check the recommendation — a green dot means the result is comfortably web-friendly. Then click Optimize & download.
Common use cases
- Faster websites. Replace a heavy WAV with a compressed MP3 so background audio, intros and clips load quickly without hurting performance.
- Podcasts & voice. Export speech to mono at 64–96 kbps for clear sound at a fraction of the size.
- Email & uploads. Shrink a recording to fit attachment limits or upload forms that cap file size.
- Trim clips. Cut a sample, ringtone or sound effect down to just the part you need before you publish it.
- Convert formats. Turn a WAV, M4A or FLAC into a universally-playable MP3 in seconds.
How it works & privacy
This tool uses the browser's Web Audio API to decode and process your file and a built-in MP3 encoder (running in a background Web Worker) to compress it. Because everything happens on your device, nothing is ever uploaded — no server round-trip, no queue, and no copy of your audio stored anywhere.
That makes it safe for sensitive recordings, fast even on large files, and fully functional offline once the page has loaded.
Limitations
- Output formats are MP3 and WAV. Opus and AAC export are not offered in this version to keep the tool lightweight and fully offline.
- Input must be a format your browser can decode (typically MP3, WAV, M4A/AAC, OGG and FLAC).
- Very long files use more memory because the whole file is decoded in the browser; trimming first helps on low-end devices.
Frequently asked questions
Is my audio uploaded to a server?
No. Decoding, trimming, resampling and encoding all run in your browser using the Web Audio API and a built-in MP3 encoder. Your audio never leaves your device, so it works offline and keeps private recordings private.
Which format should I choose for the web?
MP3 is the safe universal choice — every browser, phone and device plays it, and the bitrate control lets you trade size for quality. Use WAV only when you need a lossless, uncompressed file; it is much larger and not ideal for the web.
What bitrate should I use?
For spoken word (podcasts, voice) 64–96 kbps mono is plenty. For music on the web, 128 kbps is a great balance and 192 kbps is near-transparent. Above 256 kbps the files get heavy with little audible benefit for most listeners.
Does it work on mobile?
Yes. The tool works on phones and tablets as well as desktop. The MP3 encode runs in a background thread so the page stays responsive, and you can pick a file straight from your device.
How do I trim the audio?
Drag the two handles on the waveform to set the start and end of the part you want to keep. Press play to preview the selection, then export — only the selected region is encoded.
What files can I open?
Anything your browser can decode — typically MP3, WAV, M4A/AAC, OGG and FLAC. The output is always MP3 or WAV.
Why is mono smaller than stereo?
Mono stores a single channel instead of two, roughly halving the data for the same bitrate. For voice and podcasts mono is usually indistinguishable and a great way to cut file size.