What AVIF actually buys you
AVIF is the newest image format with real browser support behind it, and on photographs it is not a small improvement.
Here is the same frame from our test photo, scaled to 1920 pixels wide and written five ways. Every number was measured through this page’s own converter.
| Format | Size at 1920 px |
|---|---|
| AVIF, quality 40 | 39 KB |
| AVIF, quality 55 | 73 KB |
| AVIF, quality 70 | 112 KB |
| WebP, quality 82 | 139 KB |
| AVIF, quality 85 | 216 KB |
| JPEG, quality 85 | 302 KB |
| PNG | 3,911 KB |
At comparable visual quality, converting HEIC to AVIF produced a file about a third the size of the JPEG and roughly 20% smaller than the WebP.
Full resolution tells the same story. The original 4000 × 3000 HEIC was 1,409 KB. As AVIF at quality 70 it came to 365 KB — a quarter of the size of a format already known for being efficient.
And what it costs you
This is where most pages stop talking, so we will not.
Encoding is slow. AVIF compression does far more work than JPEG, and here it runs on your processor rather than someone’s server. Measured on an ordinary desktop:
| Job | Time |
|---|---|
| 1920 px, effort Faster | 3.5 s |
| 1920 px, effort Slower | 6.1 s |
| Full 4000 × 3000, Faster | 7.3 s |
| Full 4000 × 3000, Slower | 20.0 s |
The encoder is 3.4 MB. AVIF is the one format on this site that needs a real compressor rather than a file header, and that compressor is WebAssembly that has to reach your browser. It downloads the first time you convert here, cost us about 1.5 seconds, and is cached afterwards.
It loads on this page only. Nothing else on the site pays for it.
So the trade is plain: wait a few seconds, get a file a third the size. For images going onto a website that is an excellent bargain, and for a one-off share it is probably not.
How to convert HEIC to AVIF in 3 steps
1. Add your photos
Drag them in, paste, or click to browse. There is no file cap, and nothing is uploaded at this step or any other.
2. Set the quality
Seventy is the default. Open Advanced options to change it, or to switch the effort setting if you would rather trade time for a few more bytes saved.
3. Convert and download
Press Convert and wait. The first photo carries the encoder download with it; the rest do not.
Save files individually or take the whole batch as one .zip.
AVIF quality numbers are not JPEG quality numbers
This trips up almost everyone who tries the format, and it is worth its own section.
Quality 85 in JPEG is a sensible default. Quality 85 in AVIF is close to overkill: our test frame came to 216 KB, and pushing to 95 produced 618 KB, more than double, for a difference you would need to pixel-peep to find.
The equivalent of a good JPEG is somewhere around AVIF 60 to 70. At 70 our frame was 112 KB against the JPEG’s 302 KB. At 40 it was 39 KB, an eighth of the JPEG, and starting to show it on fine detail.
If you are converting for the web, leave it at 70 and only go up if a specific image looks soft. Going up is expensive here in a way it is not with JPEG.
AVIF and HEIC are cousins, and only one is welcome
This explains the whole site, so it is worth a paragraph.
Both formats put compressed images in the same kind of container. The difference is what does the compressing. HEIC uses HEVC, which is covered by a large patent pool and costs money to license. AVIF uses AV1, which was built by a consortium specifically to be royalty-free.
That single distinction is why your browser can decode and encode AVIF but will not write a HEIC under any circumstances, and it is why converting HEIC is a thing people have to do at all.
So converting HEIC to AVIF is not really a downgrade or an upgrade. It is moving the same picture from an encumbered codec into an open one that happens to compress slightly better and is welcome everywhere on the web.
Our guide on why browsers cannot create HEIC files goes through the licensing side in full.
Transparency and what else survives
Unlike JPEG, AVIF has a real alpha channel, and this converter keeps it. A HEIC with transparent areas comes out the other side still transparent, with no white background painted underneath.
What does not survive is the metadata. The image is decoded to pixels and re-encoded, so the EXIF block — shooting date, camera settings, GPS coordinates — is not carried into the AVIF. For anything you are publishing that is usually what you want. To see what a photo holds before converting, our HEIC EXIF viewer reads it locally.
Colour depth is the other honest caveat. Camera HEIF files are often 10-bit, and the output here is 8-bit. AVIF itself handles 10-bit perfectly well; our pipeline goes through a canvas, and a canvas is 8-bit.
Serving AVIF on a real website
Getting the file is the easy half. Serving it without breaking anything takes one more step.
The usual pattern is a <picture> element that offers AVIF first and lets the browser fall back:
<picture>
<source srcset="photo.avif" type="image/avif">
<source srcset="photo.webp" type="image/webp">
<img src="photo.jpg" alt="">
</picture>Browsers take the first type they support, so a visitor on something ancient still gets the JPEG. That is why we also keep HEIC to WebP and HEIC to JPG around — a good setup usually wants all three.
If your host or CDN does content negotiation for you, you may only need to upload the AVIF and let it serve the fallbacks. Check before deleting the originals.
Where AVIF works, and where it does not
Browser support is no longer the question. Chrome, Edge, Firefox, Safari and the mobile browsers all display AVIF.
Outside the browser is where it gets uneven. Plenty of desktop applications, older operating system versions, and image tools built before 2021 do not open an .avif at all.
That distinction decides which of our converters you want:
- For a website, AVIF is the right answer, with WebP as the fallback if you serve one.
- To send someone a photo, use JPG. Compatibility beats file size the moment another person is involved.
- For editing or archiving, use PNG or TIFF.
Why this page took so long to exist
There is a note in this project’s own planning documents saying AVIF was not worth building. It is worth explaining why that changed, because the reasoning matters more than the conclusion.
The original objection had two parts. The encoder is 3.4 MB, and its faster multithreaded build needs SharedArrayBuffer, which needs cross-origin isolation, which would have broken the advertising script on every page of the site.
Re-measuring both showed the objection had aged badly. The single-threaded encoder needs no cross-origin isolation at all — we confirmed the page runs with crossOriginIsolated false and SharedArrayBuffer undefined, and the conversion works anyway. And the 3.4 MB only ever loads for someone who actually converts to AVIF on this page, because the import is deferred until then.
What remained was honest cost, not a blocker: several seconds per photo. That belongs on the page rather than in a decision to skip it.
We also re-tested whether a browser can produce an AVIF without any of this. On Chrome 151, asking a canvas for image/avif still returns a PNG, silently, exactly as it did on 145. A converter that does not check what came back is handing you a renamed PNG.
The bottom line
AVIF is the best compression available for photographs on the web right now, and it is not close.
The costs are real and measurable: a few seconds of your processor’s time per image, and a 3.4 MB encoder the first time. The saving is roughly two thirds against JPEG at matching quality.
Convert HEIC to AVIF for anything that will be served over the web. Use JPG when you are handing the file to a person, because the smallest file in the world is worthless if the recipient cannot open it.