Convert Images to AVIF

Re-encode JPG, PNG, WebP, GIF, BMP and HEIC as AVIF, the smallest of the widely supported web formats, with transparency intact.

Drop your files here

.jpg, .jpeg, .png, .gif, .bmp, .webp, .heic · up to 100 MB

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How to Convert to AVIF

1
Drop your images
Up to 50 files at once. The format of each is read from its first bytes, so a file with the wrong extension still reaches the right decoder.
2
Pick quality and speed
Quality 60 is the default and is closer to JPEG 85 than to JPEG 60, because the AVIF scale does not line up with the one you are used to. Speed trades encoding time against file size.
3
Download the AVIF files
One image comes back on its own, several as pulsarkit-avif.zip, with the total saving shown next to the result.

AVIF is smaller, and slower, both by a lot

AVIF uses the AV1 video codec's intra-frame compression, which is far more sophisticated than JPEG's and noticeably better than WebP's. On typical photographs that means files 30 to 50 percent lighter than WebP at a quality you cannot tell apart. The bill arrives as processor time: encoding a 6-megapixel photo takes seconds rather than milliseconds, and a 100-megapixel one can take most of a minute. That is why the batch limit here is 50 files rather than the 100 other converters allow, and why the progress bar says outright that this step takes a while instead of pretending to be stuck. The speed setting is the dial for that trade: 0 searches hardest and produces the smallest file, 10 is nearly instantaneous and produces one 15 to 20 percent heavier, and 6 is the compromise most people should leave alone.

Where the savings are large and where they are not

How much you save depends entirely on what the source already was. A photo saved by a camera or a design tool at high JPEG quality, a large file with a lot of headroom, routinely drops by 70 percent or more. A stock photograph already compressed hard by whoever published it has much less left to give, and 25 to 30 percent is a realistic result there. That is not a fault in the encoder; there is only so much redundancy in any given file. If a result comes out heavier than the source, which can happen with an already-tight JPEG at quality 90 and above, the file is still handed to you and the page says so, rather than quietly substituting different settings than the ones you chose.

Transparency, colour detail and metadata

AVIF keeps an alpha channel, so a cut-out PNG stays a cut-out. When the transparency is a hard mask, with every pixel fully opaque or fully clear as in most logos and cut-outs, the alpha quality is raised to maximum automatically, because compressing a binary mask lossily produces a visible halo along every edge. Colour detail has its own control: 4:2:0 stores colour at half resolution and is right for photographs, while 4:4:4 stores it in full and is worth the extra bytes for screenshots, diagrams and anything with fine coloured text. EXIF metadata is dropped by default and can be kept with one switch; rotation recorded in EXIF is always applied to the pixels first, so the image is upright whether or not the metadata travels with it.

Encoding happens on your device

The AV1 encoder runs as WebAssembly inside your browser tab. Your images are read from disk into memory, encoded there, and handed back as a download. Nothing is uploaded, there is no processing queue on someone else's machine, and closing the tab discards everything. That also explains the encoding time: it is your processor doing the work, not a server farm.

Frequently asked questions

How much lighter is AVIF than WebP?

On photographs, typically 30 to 50 percent at a quality you cannot distinguish. On flat graphics and screenshots the gap narrows, because WebP's lossless mode is already efficient there. The only reliable way to know for your images is to convert a couple and compare.

Why is the encoding so slow?

Because AVIF is built on AV1, a video codec that searches through far more possible encodings than JPEG does. That search is what buys the smaller file. Raising the speed setting cuts the search short: speed 10 finishes in a fraction of the time and produces a file roughly 15 to 20 percent larger.

What does the speed setting actually change?

How hard the encoder looks for a compact encoding, not the image quality target, which is set separately. Speed 0 is the most thorough and the slowest, speed 10 the quickest and least efficient, and 6 sits in the middle. Picture quality stays roughly constant; only file size and time move.

Do browsers support AVIF?

Yes. Chrome, Edge, Firefox, Opera and Safari 16.4 and newer all decode it, which covers the overwhelming majority of visitors. If you need to cover very old browsers as well, serve AVIF with a WebP or JPEG fallback rather than replacing your images outright.

Is transparency preserved?

Yes. AVIF supports an alpha channel, so PNG cut-outs and logos keep their transparency. If the transparency is a hard on/off mask, the alpha quality is automatically forced to maximum so no fringe appears around the edges.

What is 4:4:4 subsampling for?

It stores colour at full resolution instead of halving it. Photographs almost never need it, because the eye is poor at fine colour detail, but screenshots, charts and coloured text are visibly cleaner with it. The file is larger, which is why 4:2:0 is the default.

How many images can I convert at once?

Up to 50 files, 100 MB each and 500 MB in total, all with the same settings. The limit is half what the lighter converters allow because AV1 encoding is heavy, and a queue of a hundred large photos on a modest laptop means several minutes of waiting.

Does the file get uploaded to a server?

No. Decoding and encoding both run in your browser through WebAssembly. Your images stay on your device from start to finish, and nothing remains anywhere once you close the tab.