Convert AVIF to JPG in your browser

Format rejection is the least informative failure a portal can hand you: the upload simply does not appear, or returns a generic error, because the file header says WebP or HEIC while the requirement says JPEG. Converting is a thirty-second fix that removes a whole class of dead ends.

The reverse case matters for the web. Serving WebP or AVIF instead of JPEG typically saves a quarter to half the bytes for the same visual quality, which is free page-speed improvement for anyone with a website or blog.

Conversion is one of the few operations where doing it in the browser is not merely a privacy nicety — passing a photograph through an unknown converter often adds a watermark or silently shrinks it, and neither happens here.

This tool exists for images handled in a hurry: no queue, no account, no upload, and a result you can verify on the spot. The explanation below is the same one we would give a colleague who asked how it works.

On a phone, memory is the real constraint rather than any size limit. A 12-megapixel photograph is about 36 MB once decoded into pixels, so compiling a batch of twenty and holding every result in memory at once will get a mobile browser killed well before it runs out of storage. Process batches of ten to fifteen on a phone; on a laptop the same job is unremarkable.

Choose the format from what the image is, not from what is fashionable. A photograph is a smooth continuum of tone, which JPEG handles beautifully and PNG handles expensively. A screenshot, a logo, a signature on white paper or anything with a small palette is the opposite: PNG compresses it losslessly to a fraction of what JPEG costs, and keeps the hard edges hard. WebP and AVIF are excellent for the web and are still frequently refused by government and bank upload widgets.

Accepted inputs are JPEG, PNG, WebP, AVIF, HEIC, GIF and BMP images up to 50 MB each. SVG, HTML and other script-bearing formats are refused outright rather than sanitised, because a file that can execute code has no business being re-encoded — and an upload field that accepts one is a security hole rather than a feature. Output is written as JPEG, matching the format the destination expects. Several files can be queued where the workbench supports it. Batch, page and memory limits apply; check every output.

Each format has its own decoder and encoder path. JPEG, PNG, WebP and AVIF are handled by WebAssembly codecs compiled from the reference libraries, so the same quality decisions apply as in a desktop tool. Transparency is preserved for PNG and WebP, and composited onto white for JPEG, which has no alpha channel — the opposite behaviour to naïve converters that leave transparent regions black. Repeated conversion between lossy formats is discouraged in the interface, because each pass costs a little quality. Conversion decodes to pixels and re-encodes in the target format, which is why a format change is a real operation and not a renamed extension — portals that read the file header will agree with the tool about what the file actually contains. Transparency is composited onto white for JPEG, since JPEG has no alpha channel, and preserved for PNG and WebP.