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PDF Linearization Checker

Find out whether a PDF is optimised for the web. A linearized (“Fast Web View”) PDF puts the first page and a set of hint tables at the start of the file, so browsers can show page 1 while the rest is still downloading. The checker runs qpdf’s linearization test, explains the result and creates a correctly linearized copy with one click.

  • Files stay on your device
  • No sign-up
  • Free to use

How to use PDF Linearization Checker

  1. Drop a PDF onto the page.
  2. Click “Check linearization”.
  3. Read whether it is linearized and valid.
  4. Download a linearized copy if needed.

PDF Linearization Checker features

Real check

qpdf verifies the hint tables, not just a flag.

Error detection

Finds files whose linearization was broken by edits.

One-click fix

Writes a properly linearized copy.

Compact output

Object streams generated for a smaller file.

Explanations

When linearization matters and when it does not.

Private

Processing in your browser.

When to use PDF Linearization Checker

  • Optimising large PDFs on a website.
  • Checking documents for a web portal’s requirements.
  • Fixing files that lost Fast Web View after editing.
  • Preparing catalogues and manuals for online viewing.

PDF Linearization Checker FAQ

What is linearization?

A file layout in which the objects for the first page come first, followed by hint tables that tell a viewer where every other page is. Combined with byte-range requests, viewers can show pages before the full download.

Does my PDF need it?

Only for large files viewed directly from a web server. Files sent by email or downloaded first gain nothing.

Why “linearized, but with errors”?

Programs that append changes to a file keep the old linearization dictionary but make the hints wrong. Viewers then load the whole file.

Does linearization change the document?

No. Pages, text and images stay the same; only the order of objects in the file changes.

Does the web server matter?

Yes. It must support HTTP range requests, which most do.

Is my PDF uploaded?

No. qpdf runs in your browser.

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Fast Web View and linearized PDFs

A normal PDF keeps its index at the end of the file, so a viewer must receive the whole file before it can find the first page. For a large catalogue on a slow connection, that means waiting. Linearization rearranges the file so that everything needed for page 1 comes first.

The second part of linearization is the hint tables: a compact map of where each page’s objects are. With them, a viewer that jumps to page 80 can request exactly those bytes from the server instead of downloading the pages before it.

Linearization is fragile. Saving changes incrementally – which many editors do to be fast – appends new data at the end and leaves the original hints pointing at outdated positions. The file still opens, but the speed advantage is lost. qpdf’s check compares the hints with the actual file and reports such mismatches.

The fix is to rewrite the file in linearized form, which the tool does with qpdf in your browser. The content does not change.

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