Last tested
What does this PNG to WebP converter do?
Vaultaire converts one still PNG into one still WebP inside a browser worker. It keeps the rendered image and transparency, removes source metadata, then checks the completed WebP before download.
The selected image is not sent to a conversion API. Cloudflare serves the page and its static code, but the file bytes stay in the browser. The tool stops if the browser cannot prove the output contract locally.
Lossless or lossy: which WebP should I pick?
WebP has two encodings. The tool does not guess for you, and it confirms which one the browser actually produced by reading the finished file back.
| Property | Lossless | Lossy |
|---|---|---|
| Pixels | Kept. A mismatch blocks the download | Changed on purpose. The page reports the measured difference |
| File size | Smaller than most PNG files | Usually much smaller |
| Best for | Logos, icons, screenshots, flat art | Photos and detailed pictures |
| Transparency | Preserved and checked | Preserved and checked |
| Quality control | No setting. The encoding is confirmed as VP8L | A slider from 5 to 95, set to 82 by default |
| Metadata | Source records are not copied | Source records are not copied |
The official WebP container specification defines the VP8, VP8L, alpha, and metadata chunks read back from the new file. The PNG specification defines the input chunks, color types, and animation chunks checked before decode.
How do I convert PNG to WebP without uploading it?
- Choose a PNG. Select one still PNG image. The browser checks its signature and chunks before decode.
- Pick the compression. Choose lossless to keep every pixel, or lossy and a quality value for a smaller file.
- Convert and verify. Create the WebP locally, read the size saving and the receipt, then download the verified copy.
Still PNG only. Up to 20 MB, 4,096 pixels on either side, and 16,000,000 total pixels.
PNG to WebP FAQ
How do I convert PNG to WebP?
Choose a still PNG, pick lossless or lossy, then select Convert to WebP. The browser creates and verifies a separate WebP. Your original PNG is not changed.
Is PNG to WebP lossless?
It is in lossless mode. The tool reads the new file back and blocks the download unless the WebP is a lossless VP8L image and the pixels pass the local check. Lossy mode changes pixels on purpose to make a smaller file.
Does PNG to WebP keep transparency?
Yes. WebP stores an alpha channel. Alpha values must match exactly. For partially transparent color, each premultiplied 8-bit channel may differ by at most 2 because native browser encoders can round those values. In lossless mode anything larger blocks the download.
How much smaller is WebP than PNG?
It depends on the image, so the tool measures your file and shows the exact result. Lossy mode usually saves the most. A small flat PNG can come out larger as WebP, and the page says so instead of hiding it.
Is my PNG uploaded?
No. The selected file is read, converted, and verified in a browser worker. PostHog receives tool-use events, but never image bytes, file names, dimensions, metadata, or output details.
Does converting PNG to WebP remove metadata?
Yes. Source EXIF, ICC, text, time, and C2PA records are not copied. The finished WebP is scanned again with an independent parser, and the download stays locked if any record is found.
Can it convert animated PNG to WebP?
No. Animated PNG is rejected before decode because a still WebP would discard frames. The tool does not silently export the first frame.
Should I use WebP instead of PNG on a website?
WebP usually sends fewer bytes at the same size, which makes pages load faster. Keep the PNG when you need an editable master or a format that very old software can open.
Which browsers can open a WebP file?
Chrome, Edge, Firefox, Safari 14 or later, and current Android and iOS browsers display WebP. Some older desktop apps still cannot open it.
Can I convert several PNG files at once?
Not in this release. One-file conversion keeps the memory limit, cancellation, output name, and verification result clear.