When PNG to WEBP turns PNG into WEBP
Shrink a PNG for a website while keeping transparency.
What PNG to WEBP changes in the picture
The browser encodes a WEBP. Current browsers display it.
Do not use WEBP for a printer or a government portal that lists JPG or PNG only.
When PNG to WEBP is the right page
PNG to WEBP sits on this site because PNG and WEBP are not interchangeable, even when they look similar in a file list. Shrink a PNG for a website while keeping transparency. Use PNG when a logo must stay crisp or when the background must stay transparent. Current browsers display WEBP. Older desktop apps, some CMS fields, and many printers still do not.
The browser encodes a WEBP. Current browsers display it.
What you give up by leaving PNG
PNG keeps sharp edges and transparency. Screenshots, logos, and diagrams belong in PNG. Photographs are usually much larger as PNG than as JPG, with little visual gain.
Keep the PNG master of a logo. Export JPG only for the places that refuse PNG.
What you gain, and do not gain, with WEBP
The download has to be WEBP, because that is the format the next step named. Current browsers display WEBP. Older desktop apps, some CMS fields, and many printers still do not. It is a sensible web copy of a photo or a transparent graphic.
WEBP made from a JPG cannot look sharper than that JPG.
A test that matches the real file
Start from the question the other software asked. If it asked for WEBP, PNG to WEBP is the matching page. If it asked for something else, switch tools instead of hoping a similar extension will pass. Shrink a PNG for a website while keeping transparency. The browser encodes a WEBP. Current browsers display it. The limit is the part people skip, and it is the part that decides whether the download is usable. Do not use WEBP for a printer or a government portal that lists JPG or PNG only. The file stays in your browser and is not uploaded. The limit is 100 MB. Keep the original until the download has been opened in the program that will use it. Check three things in the download: it opens, the PNG material you cared about is still there, and the file size or the layout is what the form described. A new extension alone is not those three things. If a portal, a teacher, or a client rejects the file, send them the original PNG as well when you are allowed to. PNG to WEBP is a convenience copy. It is not a new master. Photos fail uploads for three separate reasons: the format name, the pixel size, and the kilobyte size. PNG to WEBP only does the PNG to WEBP step. If the form also prints a pixel size or a 20 KB or 50 KB cap, do that step with the matching tool, starting from the original each time. A second lossy save will not recover detail.
Here is the decision for PNG to WEBP. You start with PNG and you stop when a real program accepts WEBP. Text in a screenshot stays sharper than it does in a heavy JPG. Word and print shops often reject it, so it is the wrong file for those handoffs. If those two sentences describe a tradeoff you do not want, do not convert. Renaming the extension by hand will not do this job. Running the tool twice on its own output will not do it either.
Do not use WEBP for a printer or a government portal that lists JPG or PNG only.
A related step, if you still need one, is WEBP to PNG.
Other jobs start from the homepage, where each tool is named for the conversion it actually does.