Free tool · PDF · Runs in your browser
Convert WebP to PDF
Short answer
Choose WebP files and the tool decodes them in your browser and puts each on a PDF page, with no upload.
Nothing is uploaded. JPEG and PNG files go into the PDF as they are; other formats are converted in your browser first.
Key takeaways
- PDF has no WebP: the picture is decoded and saved again, as JPEG (default) or PNG (lossless or transparent).
- As JPEG the photo grew +59% (2.33 MB to 3.72 MB); lossless it grew to 25.7 MB, 11 times the WebP.
- A WebP with transparency is saved as PNG automatically: the insignia became a 23.9 MB PDF from a 1.98 MB WebP.
- A small screenshot WebP of 57.7 KB became 128 KB as JPEG or 286 KB lossless.
- Time: 741 ms for the photograph as JPEG, 5.8 s lossless.
Measured: WebP in, PDF out
PDF cannot hold WebP, so the picture is saved again: as a JPEG at quality 0.92 (a 2.33 MB photo became a 3.72 MB PDF) or, if you tick the lossless option or the WebP has transparency, as a PNG (the same photo became 25.7 MB). Expect a PDF about 1.6 times the WebP for photographs.
Measured with the tool's own code (the same function the page runs) in headless Chromium on public domain NASA and National Archives pictures, a camera photo from Wikimedia Commons, and files we made from them. Each PDF was then opened by pdf.js, which reported its page count and page sizes, and by pdf-lib, which read back the picture streams: a JPEG in the PDF was compared byte for byte with the file you chose, and PNG pixels were compared with ffmpeg's decode.
| Picture | WebP | PDF default | Stored as | PDF lossless | Time default / lossless |
|---|---|---|---|---|---|
| Photograph WebP | 2.33 MB | 3.72 MB | JPEG 0.92 | 25.7 MB | 741 ms / 5.8 s |
| Insignia with transparency, WebP | 1.98 MB | 23.9 MB | PNG (transparent) | 23.9 MB | 5.3 s / 5.4 s |
| Screenshot WebP | 57.7 KB | 128 KB | JPEG 0.92 | 286 KB | 50 ms / 199 ms |
The sizes grow because WebP is a newer, more efficient codec than JPEG or PNG: the same picture needs more bytes in the formats PDF supports.
Why a WebP cannot go in as it is
Wikipedia lists the filters a PDF can use, among them DCTDecode (a lossy filter based on JPEG), FlateDecode (based on deflate) and JPXDecode (JPEG 2000). WebP is not among them, so any converter must decode the picture and write it in one of those. This tool uses JPEG for photographs and Deflate (PNG style) when you ask for lossless or when there is transparency.
Page size: same as the picture, A4 or Letter
The tool offers three page sizes. "Same size as the picture" sets each page to the picture at 150 pixels per inch, so a 3840 pixel wide photo becomes a page 25.6 inches wide (1843.2 points; Wikipedia gives the PostScript point as 1/72 of an inch). A4 is 595.28 × 841.89 points, which Wikipedia lists as 210 mm × 297 mm, and US Letter is 612 × 792 points, or 8.5 × 11 inches. On A4 and Letter the picture is scaled to fit inside a 0.5 inch margin, centered, and the page turns to landscape for a picture wider than tall.
Getting a smaller PDF
If the PDF is too large, leave the lossless option off, or compress the WebP to a smaller picture first.
Free tools:Convert WebP to JPGAny picture to PDFCompress an image to a target sizeJPG to PDF
JPEG or PNG inside the PDF?
| Picture | WebP | PDF with JPEG | PDF with PNG | PNG is how many times the JPEG | Time JPEG / PNG |
|---|---|---|---|---|---|
| Photograph WebP | 2.33 MB | 3.72 MB | 25.7 MB | 6.9x | 741 ms / 5.8 s |
| Insignia with transparency, WebP | 1.98 MB | 23.9 MB | 23.9 MB | 1.0x | 5.3 s / 5.4 s |
| Screenshot WebP | 57.7 KB | 128 KB | 286 KB | 2.2x | 50 ms / 199 ms |
A photograph is far smaller as JPEG. A screenshot or a picture with flat colors can be close in size either way, and transparency forces PNG, so the insignia has the same size in both columns.
What the tool does, step by step
- Your browser decodes the WebP into pixels.
- If the picture has no transparency and you did not tick lossless, it is drawn on white and saved as a JPEG at quality 0.92.
- Otherwise it is saved as a PNG, with its transparency.
- The JPEG or PNG is placed on a page of the size you chose, in the order you chose.
- The PDF is built in memory and offered as a download. Nothing leaves your device.
Questions people ask
How do I convert WebP to PDF?
Choose the WebP files above, pick the page size and download the PDF. Your browser decodes the WebP.
Why is the PDF bigger than the WebP?
WebP compresses better than the JPEG or PNG a PDF can hold. Our 2.33 MB photo became 3.72 MB.
Is it lossless?
Not by default: photographs are saved as JPEG at quality 0.92. Tick the lossless option for PNG, which is much larger.
Does it keep transparency?
Yes. A WebP with transparency is saved as PNG with a mask.
Is my picture uploaded?
No.
Can I combine several WebP files?
Yes. Each becomes a page; change the order with Up and Down.
Does it work with animated WebP?
Only the first frame is used.
What if my browser cannot read the WebP?
All current browsers can; the tool shows an error if the file cannot be decoded.
Which page size should I use?
A4 or Letter for printing; the picture size to keep the picture as large as it is.
Related
Sources and how we checked
- Wikipedia: PDF (filters) (read 2026-10-10)
- Wikipedia: Point (typography) (read 2026-10-10)
- Wikipedia: ISO 216 (A4) (read 2026-10-10)
- PDF.js (Mozilla): the reader used to check every PDF (read 2026-10-10)
Reviewed October 10, 2026. The measurements ran the tool's own code and then opened every PDF with pdf.js and pdf-lib to compare pages, sizes, text and picture bytes. The files and results are in data/seo/hub/evidence/2026-10-10/pdf.