JPG to AVIF Converter
Convert JPG to AVIF online, free
Your JPGs are heavier than they need to be. AVIF stores the same photo in about half the bytes, so pages load faster. This converts JPG to AVIF right in the browser, and yes, it works on Safari and Firefox too, not just Chrome.
Drop images here or click to upload
JPG only — up to 50MB each
- Files never leave your device
- Runs in your browser
- Free, no signup
How it works
- 1
Drop your JPG files
Drop a single JPG or up to 100 files together. Product photos, blog images, exports from a camera or editor: any JPG is supported.
- 2
Pick a quality level
Quality 78 is the sweet spot for AVIF and already looks excellent. Push to 85 for hero images, drop to 65 for content images where smaller is better.
- 3
Download AVIF files
Single files download immediately, batches arrive as a ZIP. Names are preserved with the new .avif extension, ready to serve on a modern site.
Why AVIF is the most efficient format for the modern web
Roughly half the file size
AVIF compresses far harder than JPG. The same photo is typically 40 to 60 percent smaller at matching quality, which directly shrinks page weight and improves Largest Contentful Paint.
Works on every browser
Chromium encodes AVIF natively. On Safari and Firefox, a built-in WebAssembly encoder takes over so you always get a real AVIF file, never a renamed JPG, wherever you run it.
Batch up to 100 files
Modernise a whole media library in one drop. Every JPG is encoded to AVIF in parallel across your CPU cores and bundled into a single ZIP with the original names kept.
Where this helps
Faster-loading websites
Images are the heaviest part of most pages. Converting JPGs to AVIF halves their weight, so pages render sooner and Core Web Vitals scores improve, which both visitors and search engines reward.
Lower bandwidth and CDN costs
At scale, smaller images mean less data transferred on every request. Serving AVIF instead of JPG cuts bandwidth bills and eases CDN load across every visitor, month after month.
Better experience on mobile
Visitors on slow or metered connections feel large images most. An AVIF at half the size loads twice as fast on a weak signal and uses half the data, keeping people on the page.
Modernising a media library
Have hundreds of legacy JPGs? Convert the whole folder to AVIF in one batch, keep the JPGs as a fallback, and serve both so modern browsers get the light file and the rest stay covered.
Tips that help
- 1
Be more aggressive than with JPG
AVIF holds quality far better than JPG, so a setting that would look rough as JPG looks clean as AVIF. Start at 78, and try 65 for content images. Most of the time you will not see the difference.
- 2
Always keep a JPG fallback for the open web
Older browsers and software cannot read AVIF. Serve it inside a picture element with a JPG fallback so modern browsers get the small file and everything else still shows the image.
- 3
Do not send AVIF to forms or email
Upload forms, email clients, and print shops often reject AVIF. Use it for pages you control. For files headed to a form or an inbox, stick with JPG or PNG.
- 4
Expect encoding to take a beat longer
AVIF does more work than JPG to reach its smaller size, so each image takes a moment, especially large ones. The work runs across your CPU cores, and the smaller file is the payoff.
- 5
Convert in batches to save time
Drop a whole folder of JPGs at once. They encode in parallel and return as a single ZIP, which is far faster than converting one file at a time.
JPG to AVIF: cut image weight in half without cutting quality
JPG has carried the web for three decades, but it was designed in an era of dial-up and small screens, and its compression has barely changed since. AVIF is the modern answer: built on the AV1 video codec, it stores the same photo in roughly half the bytes at the same visual quality. For anyone who cares about page speed, Core Web Vitals, or bandwidth costs, converting JPG to AVIF is one of the highest-leverage changes you can make. This guide covers how much you actually save, the compatibility you trade for it, why encoding takes a beat longer, and the quality settings that keep AVIF looking sharp. imgkilo encodes AVIF in your browser, with no upload and no signup, on batches of up to 100 files at 50 MB each.
Why AVIF is so much smaller than JPG
JPG compresses by breaking an image into small blocks and discarding the fine detail your eye is least likely to notice. It works, but the method is from 1992 and it leaves a lot of redundancy on the table, which is why JPG files are larger than they need to be by modern standards.
AVIF borrows the machinery of the AV1 video codec, which spends far more effort modelling how pixels relate to one another. It uses smarter prediction, larger and more flexible blocks, and a more efficient entropy coder. The result is dramatically better compression for the same perceived quality.
In practical numbers, a 300 KB JPG photo typically becomes a 130 to 170 KB AVIF that looks identical. A large hero image that was 800 KB as JPG can drop under 400 KB. Across a page with a dozen images, that is the difference between a heavy load and a fast one.
AVIF also avoids JPG's worst artifacts. The blocky edges and colour smearing that JPG shows at low quality are largely gone, so AVIF still looks clean at settings where JPG would fall apart. You get both a smaller file and a cleaner one.
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What converting to AVIF gives your website
The first win is speed. Images are usually the heaviest thing on a web page, so halving their weight directly shrinks total page size. Pages render sooner, the largest image paints faster, and your Largest Contentful Paint score, a Core Web Vitals metric Google watches, improves.
The second win is bandwidth. If you serve images at any scale, smaller files mean lower transfer costs and less strain on your CDN. For a busy site the savings from AVIF compound across every visitor and every request, month after month.
The third win is headroom on mobile. Visitors on slow or metered connections feel large images the most. An AVIF that is half the size loads twice as fast on a weak signal and uses half the data allowance, which keeps people on the page instead of bouncing.
None of this requires sacrificing how the image looks. Because AVIF is so efficient, you keep the same visual quality the JPG had, just in far fewer bytes. The upgrade is almost free in quality terms, which is what makes it worth doing in bulk.
The compatibility trade, stated plainly
AVIF is new, and that is its one real weakness. It is decoded by current versions of Chrome, Edge, Firefox, and Safari, and by recent phones, which covers the large majority of web traffic. But older browsers, older operating systems, and a lot of desktop software cannot read it.
For the open web this is solved with a fallback. The standard pattern is a picture element that offers AVIF first and a JPG second, so modern browsers take the small AVIF and everything else gets the JPG. Visitors never see a broken image, and most of them get the lighter file.
Where you should be careful is anywhere you do not control the reader. Email clients, upload forms, print shops, and old apps may reject AVIF outright. If a file is headed somewhere like that rather than onto a web page, JPG or PNG is the safer format to send.
So the rule is about destination. AVIF is the right format for images you publish on a modern site with a fallback. It is the wrong format to email to someone on a dated machine or to submit to a form that lists only JPG. Match the format to where the file is actually going.
Why encoding AVIF takes a little longer
Making an AVIF is more work than making a JPG. The encoder searches harder for the most efficient way to represent each region of the image, which is exactly why the output is so much smaller. That search costs processing time, so each file takes a moment longer to convert.
On Chromium browsers the encode runs through the browser's own native AVIF support, which is quick. On Safari and Firefox, which do not yet encode AVIF themselves, imgkilo falls back to a WebAssembly build of the libavif encoder. It downloads once, caches, and then runs at full speed on your device.
For a single image the wait is barely noticeable. For a batch of large photos it adds up, but the work is spread across your CPU cores rather than handled one at a time, and nothing is queued behind a server. You are trading a few seconds of local processing for files that are half the size.
If you are converting a large batch and want it faster, the quality setting helps. Slightly lower quality encodes quicker and produces even smaller files, and because AVIF holds up so well, you can often drop the setting without seeing any difference.
Choosing a quality setting for AVIF
AVIF quality does not map one-to-one to JPG quality. Because the format is so efficient, a setting that would look rough as JPG looks clean as AVIF. You can compress harder than your JPG instincts suggest and still get an excellent image.
A quality of 75 to 80 is the practical sweet spot for photographs and already looks superb. Many sites push AVIF down to 60 or 65 for content images and still pass quality review, because AVIF degrades gracefully instead of breaking into blocks the way JPG does.
Reserve the higher settings, 85 and up, for hero images and anything where a viewer will look closely. There the extra quality is worth the extra bytes, though even at 85 an AVIF is usually smaller than a mid-quality JPG.
The takeaway is that AVIF lets you be more aggressive. Start at 78, view the result, and only raise the setting if you can actually see a difference. Most of the time you will not, and the smaller file is the better choice.
How the conversion works on your device
When you drop a JPG, your browser decodes it into raw pixels and draws them onto an HTML canvas at full resolution. Those pixels are then handed to the AVIF encoder, either the browser's native one or the WebAssembly fallback, which produces the compressed AVIF file.
JPG has no transparency, so there is nothing to lose on that front. The colours are carried straight across, and because the source is already standard dynamic range, the AVIF is a faithful, smaller copy of the same image rather than a reinterpretation of it.
Everything happens locally. The original JPG never leaves your device, the encoder runs in your browser tab, and the finished AVIF is handed back for download. There is no upload, no server round-trip, no account, and no limit on how many files you run through.
Because there is no server in the loop, the only ceiling is your device's memory. A modern laptop handles a folder of large photos comfortably, and the moment one batch finishes the queue is ready for the next.
Converting a whole folder of JPGs at once
Most sites do not have one image to modernise, they have hundreds. Drop a whole folder of JPGs onto imgkilo and every file is encoded to AVIF in parallel using a worker pool, then bundled into a single ZIP with the original filenames kept intact.
Up to 100 files at 50 MB each go in one batch. A set of web-sized product photos converts quickly; large full-resolution images take longer because AVIF encoding is heavier, but the batch still runs across your cores rather than one file at a time.
Since nothing uploads, there is no per-file fee, no watermark, and no plan to buy. Batch size is limited only by your machine, not by a server quota, so you can modernise an entire media library in a handful of passes.
If you want to keep a JPG fallback alongside each AVIF for a picture element, simply keep your originals. Convert a copy of the folder to AVIF here and serve both, AVIF first and JPG second, so modern browsers get the small file and the rest stay covered.
Frequently asked questions
Honest answers to what people ask before using this tool.
Further reading
Independent references if you want to go deeper on the formats and tradeoffs.