Convert BMP to AVIF

Convert BMP to AVIF online, free and 100% in your browser. No upload, no signup, no size limit — WebAssembly does the work on your device.

How to convert an image

  1. Drop or pick your BMP file — or paste it with Ctrl/⌘+V.
  2. AVIF is already selected as the target; tune the quality slider if you like (default 60).
  3. Convert, compare the before/after, and download — all on your device.

Why convert to this format?

BMP is an uncompressed bitmap that produces very large files — fine for editing, wasteful for sharing. AVIF is the newest AV1-based format — the smallest files of all, with transparency and wide-gamut color.

OptImg runs the same Rust codecs desktop tools use, compiled to WebAssembly, so you get desktop-grade AVIF output at a sensible default (quality 60) — adjustable at any time — without ever uploading your image.

Everything happens locally: your BMP is decoded, re-encoded to AVIF and handed straight back as a download. No server sees a single byte, which is why there's no queue and no file-size cap.

Frequently asked questions

Is my BMP uploaded to a server?
No. The BMP-to-AVIF conversion runs entirely in your browser with WebAssembly — your file never leaves your device, there is no queue, and no size limit beyond your device's memory.
Why is AVIF slower than the other formats?
AVIF uses the AV1 video codec, which trades encode time for the smallest files. Small images finish in a moment; very large photos can take a minute or more — the tool warns you first and you can cancel anytime.
Will converting BMP to AVIF lose quality?
AVIF is lossy, tuned to a visually transparent default (quality 60) that you can raise or lower with the slider. If the conversion can't produce a smaller file than your original, we hand the original back instead.
Is the BMP to AVIF converter free?
Yes — completely free, with no signup, no watermark and no cap on how many files you convert. There is nothing to install; it runs in your browser.