AVIF vs. WebP in 2026: what we see across 40 million transforms

Every format comparison starts with a lab benchmark. Ours starts with production: forty million transforms requested by real browsers over September.

Size

At matched SSIM, AVIF files were 27% smaller than WebP on photographs and 9% smaller on screenshots and UI captures. On flat illustrations the gap almost disappears.

Encode time

AVIF still costs more to produce. Our p50 encode time for a 1200px image is 140 ms for AVIF against 38 ms for WebP. Because results are cached, that cost is paid once per variant.

What we changed

fmt=auto now prefers AVIF for photographs above 600px and WebP for everything else. If you pin a format, nothing changes for you.