2026-09-21
WebP is usually described as 25 to 34 percent smaller than JPEG. The number is real, but the reason is not harder compression. WebP carries three different encoding modes, each aimed at a different kind of image.
Lossy WebP borrows intra-frame compression from the VP8 video codec. The key difference from JPEG is prediction: JPEG slices the image into 8x8 blocks and treats each independently, which is what produces visible blocking at high compression. VP8 predicts from neighbouring pixels with larger, more flexible blocks, so those artifacts show up later.
The practical result: at a quality level most people would accept, WebP files land roughly a quarter smaller than the equivalent JPEG. Photographs, gradients, and noisy images all benefit.
Lossless WebP targets what PNG does well: icons, UI screenshots, line art, and anything needing an alpha channel. It uses more efficient entropy coding and can apply an extra pass over an already-compressed colour table.
On this class of image, lossless WebP is typically 20 to 30 percent smaller than PNG with zero pixel loss. It is the most predictable saving available.
This is the category JPEG cannot reach at all. JPEG has no alpha channel, so transparent images previously had to be PNG (large) or flattened onto a background. WebP's lossy mode keeps alpha, letting you compress photographic quality while preserving transparent regions.
The lossy quality scale runs 0 to 100, but it does not line up with JPEG's. WebP at 75 to 80 usually matches the perceived quality of JPEG at 85 or above, and returns fall off quickly beyond that.
Start at 80 and step down, checking smooth gradients — sky, skin — at 100 percent zoom for banding. The moment banding appears, go back one step.
Chrome, Edge, Firefox and Safari 14 and later all handle WebP. Safari's support from version 14 covers both lossy and lossless modes, which is a large part of why adoption climbed quickly after 2020.
If you need older clients, the HTML picture element provides a fallback without any server-side content negotiation.
No. AVIF is smaller in most cases but slower to encode with slightly narrower support. The current safe pairing is WebP as the default with AVIF where you can afford it.
Lossy conversion does, but less than JPEG at comparable perceived quality. Lossless mode loses no pixels at all.
Usually because the source was already optimised, or the image is tiny. Converting an already-optimised PNG to lossless WebP can save nothing or even cost a few bytes.
Yes. That is one of its main advantages over JPEG, and both lossy and lossless modes support an alpha channel.