WebP and AVIF are the two modern image formats built to replace JPG and PNG on the web. Both are smaller and better, but they are not interchangeable. Here is the practical comparison.
AVIF: smaller, newer
AVIF (based on the AV1 video codec) generally produces the smallest files of the two, often noticeably smaller than WebP at the same quality, and it handles high dynamic range and wide colour well. The catch is that it is newer: support in older browsers, editing tools and upload systems is thinner, and encoding can be slower.
WebP: smaller, everywhere
WebP has been around longer and is supported by every current browser and a wide range of tools. It is still much smaller than JPG or PNG, supports transparency and animation, and is the safer default when you need broad compatibility today.
How to choose
- Maximum compression, modern audience: AVIF — best size, if your pipeline and visitors support it.
- Broad compatibility, still small: WebP — the pragmatic default for most websites.
- A tool rejected your AVIF or WebP: convert back to JPG or PNG.
Converting between them
You can move images between these formats in your browser without uploading: AVIF to WebP for broader support, PNG to WebP to shrink graphics, or WebP to JPG when an old system refuses WebP. If a file also needs to hit a size limit, follow up with the WebP compressor. For a fuller primer on the classic formats, see JPG vs PNG vs WebP.
How much smaller, in practice
The headline claims are easy to find and hard to pin down, because the answer depends entirely on the picture. For ordinary photographs, WebP typically lands around twenty five to thirty per cent below a JPG of comparable quality, and AVIF usually goes further again, often another twenty per cent or more below WebP. The gap widens on images with large areas of smooth gradient, such as skies and studio backgrounds, and narrows on busy detailed scenes. For flat graphics, logos and screenshots with few colours, both formats beat PNG by a wide margin, and the choice between them matters less than the choice to move off PNG at all.
Support is no longer the deciding factor
For several years the honest advice was to use WebP because AVIF support was patchy. That argument has mostly expired: every current major browser decodes AVIF. The remaining friction is not the browser but everything around it. Older operating systems, desktop photo viewers, email clients, content management systems, and the upload forms on government and banking portals are often years behind. WebP has had longer to spread through that long tail, so it is the safer bet when a file is going to be handled by software you do not control.
Encoding speed is the real trade
AVIF files take noticeably longer to create than WebP ones, because the compression does more work. For a handful of images that is irrelevant. For a large batch, or a site that generates images on demand, it becomes a genuine cost in time or server capacity. Decoding, which is what your visitors experience, is fast enough in both cases that it is not usually worth worrying about.
A simple way to choose
If the image is for a website you control and you are optimising page weight, AVIF is the better choice, ideally served with a WebP or JPG fallback so nothing breaks. If the file is going to be sent to somebody, uploaded to a portal, or opened in software you cannot predict, use WebP, or convert to JPG outright. If you are not sure which situation you are in, WebP is the lower risk answer and still a large improvement over JPG.
Converting either way
The image converter moves files between these formats in your browser, including PNG to WebP and WebP to JPG when something refuses to open a modern file. If size rather than format is the actual problem, compressing a JPG to an exact target with the image compressor often solves it without any format change at all.