Convert Image to AVIF

It tells you what your browser can do

An unusual thing for a converter to do, and the reason to use this one.

AVIF encoding here happens in your browser, not on a server. That is what keeps your files private and makes it free and unlimited — but it also means the result depends on the browser you are using, because not every browser ships an AVIF encoder.

Rather than assume, the tool runs a quick test and reports the answer in the options panel before you do anything:

"AVIF format supported by your browser" means you get real AVIF files.

"AVIF not supported — will fall back to WebP" means your browser can display AVIF but not create it, so you will get WebP instead. Each converted file is labelled so you can see exactly which ones fell back.

That matters because a silent fallback is a genuine trap. A tool that hands you a file named .avif containing WebP or PNG data will pass unnoticed until something downstream rejects it — and then the bug is very hard to find. Here you know before you start.

If the fallback fires and you need real AVIF: current Chrome and Edge can encode it, and Firefox support has been arriving. Opening this page in a recent Chrome is usually the whole fix. Failing that, a command-line tool (`avifenc`, or ImageMagick built with AVIF support) or a build step in your site's pipeline will do it — and for a site, the build step is the right answer anyway.

Why AVIF, and what it costs

Worth being even-handed, because most pages about AVIF only sell it.

What you gain: AVIF is typically 20 to 50 per cent smaller than WebP at the same visible quality, and around half the size of a JPEG. It keeps fine detail and gradients better at low file sizes, handles transparency, and supports wide colour and HDR. For a page carrying a lot of photographs, the bandwidth saving is the largest single win available from image formats today.

What it costs:

Encoding is slow. AVIF compression does far more work than JPEG or WebP, so converting takes noticeably longer — seconds per image rather than an instant, and longer for large photographs. That is fine for a batch you run once, and it is why you would not do it on the fly for every request.

Tooling support is still uneven. Browsers display AVIF almost universally now, but the software around it lags — some image editors, CMS uploaders, email clients, social platforms and older build tools still will not take it. Test the thing that will consume your file before converting your whole library.

Small and simple images barely benefit. For icons, logos, flat graphics and anything with large areas of one colour, a well-optimised PNG or WebP is often the same size or smaller, and far more widely accepted. AVIF's advantage is on photographs.

How to use it on a real website

The honest answer is that you should not simply replace your images.

Serve AVIF with a fallback, so browsers that cannot display it still get something. In HTML that is the picture element with an AVIF source first, a WebP source second and a JPEG or PNG as the final img. Every browser takes the best format it understands and nobody sees a broken image.

That also means keeping your originals. Do not convert and delete — you need the JPEG for the fallback, and you will want the original if you ever re-encode at a different quality.

And measure rather than assume. Convert a handful of your heaviest images first, compare the file sizes, and look at them side by side at the quality you have chosen. Sometimes the saving is dramatic; on an image that was already well optimised it can be modest.

Choosing a quality

The slider defaults to 85%, which is a sensible general setting and roughly where AVIF stops being visibly different from the original.

AVIF holds up better at low settings than JPEG does, which is the interesting part: 60 to 70 per cent often still looks clean where the same number in JPEG would show obvious blocking. If page weight is your priority, that is the range worth testing, and it is where the format earns its reputation.

Go above 90 only for images with fine detail that matters — product photography, artwork, anything that will be zoomed. The file grows quickly up there and the visible gain is small.

The usual rule applies: convert from the best original you have, not from an already-compressed copy. Re-encoding a low-quality JPEG into AVIF preserves its existing flaws in a smaller file rather than fixing them.

Everything runs on your own device. No upload, no watermark, no account, and no daily conversion limit — which is the practical difference from the image-CDN services whose free tier is a sample of a paid product.

Related tools

Convert Image to WebP produces WebP, which is the format to use when you need near-universal support rather than the smallest possible file — and it is the fallback you would pair with AVIF. Compress Image optimises JPEG and PNG in place, which is often enough. Resize Image reduces the dimensions, which usually saves more than any format change.