Why does my PDF have so many nearly-empty pages?

A forty-page document with about eight pages of actual content in it is not unusual. It is what a template does when nobody is watching.

The four usual causes

Section breaks. Most report templates start each chapter on a new page, and many start it on a new *odd* page — which is a printing convention for double-sided binding and produces a blank sheet whenever a chapter ends on an odd page. Perfectly correct, and completely pointless if the document is only ever going to be read on a screen.

Keep-with-next and table protection. A word processor will not split a table across pages if it can avoid it, and will not leave a heading stranded at the bottom of a page. Both rules push content down. A table that is one line too long for the space left moves entirely to the next page, leaving most of the previous one empty.

Fixed-height elements. An image sized to "fill the width" of a page in a portrait document can be tall enough that nothing else fits beside it. Charts exported at a fixed size do the same.

Explicit page breaks nobody removed. Someone inserted them while drafting to make a section start where they wanted, then the text around it changed and the breaks stayed.

How to see how bad it is

Open the PDF and look at the page thumbnails rather than the pages. Whitespace is obvious at that size in a way it is not when you are reading.

Or measure it: run the document through SmartShrink, which reports how much of each sheet contains ink before it changes anything. A document where most pages are under half full is a document with a page-count problem, not a content problem.

Fixing it at the source

If you still have the original file, this is worth doing properly:

• Turn off "start on odd page" unless the document is genuinely going to be bound.
• Allow tables to split, or set the rule to keep only the header row with the table.
• Remove manual page breaks and let the flow decide.
• Check images that are sized as a fraction of the page rather than in real units.

This is the better fix, because the next export will be right too.

Fixing it in the PDF you already have

Often the original is not available — it came from someone else, or it was generated by a system you do not control. In that case the document has to be repaired as a PDF.

SmartShrink measures the content box on each page and stacks consecutive sparse pages onto single sheets at full size. Pages that are already full are left alone. The output is a shorter document with the same text at the same size.

Two things it deliberately will not do: it will not shrink a dense page to make the total look better, and it will not combine pages carrying links or form fields, because embedding those loses the annotation. Both refusals are the tool being careful with your document rather than being clever with the number.

What this is not

It is not compression. If your problem is that the file is too heavy to email, the page count is irrelevant and Compress PDF is the tool — see the comparison.