free forever · private by design
Free online file converter—
images, PDF, audio & video, in your browser.
Optimal Convert converts HEIC, JPG, PNG, WebP, PDF, MP3, WAV, MP4 and more — with no uploads. Every conversion runs locally in your tab via WebAssembly and the browser’s native codec stack, so files stay private, conversions are unlimited and the app works offline.
What can you convert?
Four format families, each with its own converter page and the specific conversions below it. Any conversion you don’t see here still works in the main app.
Frequently asked questions
Is Optimal Convert really free and unlimited?
Yes. There is no account, no watermark, no queue, no daily cap and no file-size limit. Convert as many files as you like — the work happens on your own device, so there is nothing for us to meter.
Are my files uploaded to a server?
No. Optimal Convert has no upload endpoint: files are read, converted and saved entirely inside your browser tab. Your bytes never leave your device, which also means you can convert offline after the first visit.
Which formats can I convert?
Images: JPG, PNG, WebP, HEIC, SVG, GIF, AVIF, BMP and ICO, plus multi-image to PDF. PDF pages to JPG/PNG/WebP. Audio: MP3, WAV, FLAC, OGG, M4A, AAC and MP4 audio tracks. Video: MP4, MOV, MKV and AVI to WebM. Converters you don’t see on a page still work from the main app.
How does conversion run in the browser?
Each format uses the right on-device engine: libheif WebAssembly for HEIC, the browser image pipeline and canvas for photos, pdf.js for PDFs, the Web Audio API plus LAME for audio, and MediaRecorder for WebM video. Everything is cached so later visits work offline.
Private by design
This page runs entirely in your browser. Files are read, converted and saved on your own device using WebAssembly and the browser’s native codecs — nothing is uploaded, there is no account, and your bytes never leave your machine. Not even we can see them.