WebP is lossy or lossless depending on the encoder, with alpha and animation. PDF is a frozen page layout with no heading structure a machine can rely on. ImageMagick sits between the two, and this page says exactly what happens to a WEBP file on the way to becoming a PDF one.
What runs when a WEBP file becomes PDF
ImageMagick 6.9.12, on a machine we rent and watch. Your WEBP file is uploaded once, ImageMagick runs once, the PDF comes back, and neither file is kept. WEBP to PDF is one of the 3649 pairs that engine was probed on with a real file, which is why it has a page here and why the pairs the probe could not prove do not.
What survives from the WEBP into the PDF
The pixel dimensions of your WEBP file. The PDF comes out the size the WEBP went in, because nothing on this path resizes anything.
What WEBP to PDF costs you
Transparency. PDF has no alpha channel, so the engine composites your WEBP image onto white before encoding. Without that step ImageMagick lays black underneath, and a transparent WEBP logo comes back as a black rectangle.
The chance of getting text out. The PDF you receive is one page with your WEBP picture painted on it. Words inside the WEBP stay pixels, and nothing reading that PDF will find them.
If a model is going to read the PDF
Worth knowing before the PDF goes anywhere near an assistant: this is the wrong direction for that. A PDF is a set of positioned glyphs, and a model has to reconstruct the reading order before it can begin. If a machine rather than a person is going to read this WEBP file, convert it to Markdown instead and skip the reconstruction entirely.
WEBP to PDF, measured rather than promised
Running WEBP to PDF against the real engine with a real file, ImageMagick wrote 94,782 bytes of PDF in under a tenth of a second, machine otherwise idle. That is one WEBP file on one day and not an average, which is why the number is given together with the file that produced it.
The WEBP to PDF verdict was reached by a format signature, meaning at least four bytes unique to the format were found at the right offset. Which check was used matters, because they do not all prove the same thing, and a status code of 200 proves nothing whatsoever about whether the PDF file has anything inside it.
The same WEBP file, sent somewhere else
Other outputs the probe measured out of a WEBP file, so the cost of choosing PDF can be read against something. Sizes do not compare across engines, because each family was probed with its own WEBP witness file.
WEBP to JPG: 2,340 bytes in under a tenth of a second, verified by a format signature.
WEBP to PNG: 4,003 bytes in under a tenth of a second, verified by a format signature.
WEBP to GIF: 4,744 bytes in 0.1 seconds, verified by a format signature.
WEBP to TIFF: 72,264 bytes in under a tenth of a second, verified by a format signature.
Other ways into PDF, and what they measured
Among the published routes into PDF, WEBP is the fifth largest output of the 26 measured. The witness files differ, so this ranks the probe run and not your document.
TIFF to PDF: 118,721 bytes in under a tenth of a second.
SVG to PDF: 4,195 bytes in under a tenth of a second.
HEIC to PDF: 94,782 bytes in under a tenth of a second.
BMP to PDF: 118,745 bytes in under a tenth of a second.
GIF to PDF: 1,092,578 bytes in 0.9 seconds.
What we will not pretend about WEBP to PDF
A WEBP file over 25 MB is refused before the upload finishes rather than after it, so you do not wait for a rejection.
A WEBP to PDF run that passes 30 seconds is killed, and the ImageMagick process is killed with it. A run left behind would sit on one of the machine's two cores until somebody noticed.
No text is read out of the WEBP anywhere on this path. Converting a picture to PDF never turns it into words, whatever the picture happens to contain.
ImageMagick was not saturated at sixteen simultaneous conversions: it held 47.5 a second while latency moved from 0.22 s to 0.34 s, and the service memory did not move off 51 MB. That is the measured headroom behind WEBP to PDF, not a marketing number.
One WEBP file at a time, chosen in the browser. There is nothing else to set up and nothing else on offer.
WEBP to PDF: what people ask
What actually converts my WEBP file to PDF?
ImageMagick does it, 6.9.12, on a machine we rent and watch. Not a browser trick and not somebody else service: the WEBP file is uploaded once, ImageMagick runs once, the PDF comes back, and neither file is kept afterwards.
How long does WEBP to PDF take?
On the file the probe used, ImageMagick took under a tenth of a second and wrote 94,782 bytes of PDF. That is one real measurement on one real WEBP file, not an average and not a promise about yours: a larger WEBP takes longer, and past 30 seconds the run is stopped.
What do I lose going from WEBP to PDF?
The one to know about first: Transparency. PDF has no alpha channel, so the engine composites your WEBP image onto white before encoding. Without that step ImageMagick lays black underneath, and a transparent WEBP logo comes back as a black rectangle.
Can I put several WEBP files into one PDF?
No. One WEBP file goes in and one PDF comes out, with that picture on it. Nothing here merges files, orders them or numbers pages: it is one upload, one conversion, one download, and that is the whole of what this page does.
Is WEBP to PDF free?
There is a free allowance every month, and one WEBP to PDF conversion costs half a credit against it. When the allowance runs out the tool says so and stops, rather than quietly handing you a worse PDF.