Linearize a PDF for Fast Web View
When a PDF is opened from a website, an ordinary file has to arrive in full before page one can be drawn. A linearized PDF — Adobe calls it Fast Web View — is laid out so that everything needed for the first page comes first, followed by hint tables that tell the viewer where every other page lives. The first page appears almost immediately and later pages are fetched on demand.
The Linearize PDF tool checks whether a file is already linearized, explains what is wrong if the linearization is broken, and rebuilds the file with the qpdf engine. It then runs qpdf’s own linearization check on the result and shows the size before and after.
It is useful for anyone publishing PDFs online: product catalogues, research papers, annual reports, menus, manuals and e-books. The file is processed in your browser and never uploaded.
How to linearize a PDF
- Drop a PDF onto the upload area or click it to choose the file.
- Read the status: Not linearized, Already linearized or Linearization broken, along with the page count and PDF version.
- If the PDF is password-protected, type its password. The result keeps the same password.
- Leave Pack small objects into object streams ticked for a smaller file, and press Linearize PDF.
- The linearized copy downloads as yourfile-linearized.pdf; upload it to your website in place of the original.
Linearize PDF (Fast Web View) features
Fast Web View check
Finds the linearization parameter dictionary at the start of the file and compares its recorded length with the real file size.
Explains broken linearization
Files edited after linearizing keep the old dictionary but lose the benefit. The tool tells you when that has happened.
qpdf linearization
The file is rebuilt with qpdf’s linearizer, which writes the first-page section and the page offset and shared object hint tables.
Verified result
The output is checked with qpdf --check-linearization before download, and the before/after size is shown.
Works with protected files
Type the password and the linearized copy keeps the original encryption and permissions.
Private
Everything runs in your browser with WebAssembly. Nothing is uploaded.
How linearization works
Linearized PDF is defined in Annex F of the PDF specification (ISO 32000-1 and ISO 32000-2). A linearized file begins with a small linearization parameter dictionary recording the file length (/L), the first page’s object number (/O), where the first page ends (/E), the page count (/N) and the location of the hint stream (/H). The objects for page one follow, then the rest of the document.
The benefit depends on the web server too. The viewer fetches later pages with HTTP range requests, so the server must answer them (it sends Accept-Ranges: bytes). Most web servers and CDNs do this by default, and the PDF viewers built into Chrome, Edge and Firefox make use of it.
When linearizing is worth it — and when it is not
- Worth it: PDFs of a few megabytes or more that people open in a browser — catalogues, reports, scanned books, brochures with large images.
- Little gain: small files under about 1 MB, and PDFs that people download and open locally, because the whole file is on disk anyway.
- Size: hint tables add a little data, so a linearized file can be slightly larger. Packing objects into object streams usually more than makes up for it; for a real size cut use Compress PDF first, then linearize.
- Signed PDFs: linearizing rewrites the file, so an existing digital signature would show as invalid. The tool warns you when it finds one.
- Edit, then linearize: merging, filling forms or saving changes in another app usually breaks linearization, so make linearization the last step.
Linearize PDF (Fast Web View) FAQ
What does “Fast Web View: No” mean in Adobe Acrobat?
It means the PDF is not linearized, so a browser must download the whole file before it can show the first page. Run it through Linearize PDF and the property changes to “Fast Web View: Yes”.
How do I check if a PDF is linearized?
Drop it into this tool. It reads the linearization dictionary at the start of the file, checks that the recorded length matches the real size and runs qpdf’s linearization check.
Does linearizing a PDF reduce its size?
Not by itself — the hint tables add a little. With object streams packing turned on, the file often ends up about the same size or smaller. To shrink large images, use Compress PDF first.
Why does my PDF say linearized but still load slowly?
Its linearization is probably out of date: the file was changed after linearizing, often by an incremental save. The tool detects this. Rebuilding fixes it, provided your web server supports range requests.
Is linearizing the same as optimizing a PDF for web?
Linearizing is the part that lets a PDF load page by page over the web. “Optimizing” often also means compressing images and removing unused data, which you can do with Compress PDF before linearizing.
Is my PDF uploaded anywhere?
No. The qpdf engine runs as WebAssembly in your browser, and the file never leaves your device.