AVIF vs WebP
AVIF wins on file size. WebP wins on everything else that is practical. Here is where each one earns its place.
The short answer
Make WebP your default. Add AVIF on top for the images that actually matter to your page weight — the hero, the product shots, the large photographs above the fold. Serving both through a <picture> element costs you nothing at runtime and gets each visitor the smallest file their browser can read.
How they compare
| AVIF | WebP | |
|---|---|---|
| Compression vs JPEG | 40–60% smaller | 25–35% smaller |
| Compression vs each other | Roughly 20–30% smaller than WebP | Baseline |
| Encoding speed | Slow — seconds per image | Fast |
| Browser decode support | All current browsers | All current browsers |
| Browser encode support | Limited; varies by browser | Broad |
| Transparency | Yes | Yes |
| Colour depth | Up to 12-bit, HDR capable | 8-bit |
| Best at | Photographs, gradients, large images | Everything, quickly |
Where AVIF genuinely shines
AVIF is derived from the AV1 video codec, and it inherits some genuinely modern tricks. Two situations show the biggest wins:
- Smooth gradients — skies, studio backdrops, soft shadows. WebP tends to band here; AVIF holds together at surprisingly low bitrates.
- Aggressive compression. Below roughly quality 50, AVIF degrades gracefully into softness while WebP develops blocky artefacts.
It is also less impressive than its reputation on small images. Under about 200×200 pixels the container overhead eats the savings, and a WebP or even a PNG can win outright.
The catch: encoding
AVIF decoding is fast and universal. AVIF encoding is neither. It is computationally expensive — often ten times slower than WebP — and browser support for encoding lags well behind support for decoding. That is why our converter shows the AVIF output option only when your browser can actually produce one, rather than silently handing you something else.
What this means in practice
- Batch-converting a hundred images to AVIF in a browser will take real time. Start with the handful that dominate your page weight.
- Quality numbers are not comparable across formats — AVIF at 55 often matches WebP at 75.
- Always check the resulting size. On small or flat images AVIF sometimes loses.
Serving them together
The right pattern is a cascade, not a choice. Inside a <picture> element, list AVIF first, WebP second, and a JPG in the <img> fallback. Every browser takes the first source it understands, so the newest get the smallest file and nobody gets a broken image.
- Export your responsive widths as WebP — this is your reliable baseline.
- Export AVIF versions of the few largest, most visible images.
- Write the <picture> markup with AVIF, then WebP, then the JPG fallback.
- Set width, height and alt on the <img> so the layout does not shift while loading.
Is it worth the trouble?
For a hero image on a page you care about, yes — shaving 30% off the largest asset moves Largest Contentful Paint measurably. For a gallery of thumbnails, almost certainly not; the per-image savings are small and the encoding cost is real. Spend the effort where the bytes are.