Resize PDF Page Dimensions

How to change PDF page size — 3 steps

1. 1

   Add your PDF

   Drop the document in. It is rebuilt in your browser, so nothing about its contents is transmitted.

2. 2

   Choose the new page size

   Pick a standard size such as A4 or Letter, or enter your own dimensions. Decide whether the content should scale to fit or stay at its original size on the new page.

3. 3

   Download the resized document

   Every page is written at the new size and your original file is left untouched, so you can try a different setting if the first result is not right.

Page size and file size are different things

The word 'resize' does double duty and the confusion is worth clearing up first, because reaching for the wrong tool wastes time. This changes the physical dimensions of the pages — turning a Letter document into A4, or fitting an oversized page onto something a normal printer can handle. It is about the shape of the paper, not the weight of the file.

If what you actually want is a smaller file in megabytes — because an email attachment was rejected or an upload form has a limit — that is compression, and it works on a different part of the document entirely. Compression reduces the embedded images and streams that account for most of a large PDF's bulk. Changing page dimensions barely affects the file size at all, since the same text and images are still in there.

It is easy to tell which you need from the symptom. A document that prints wrongly, gets clipped at the edges, or has pages of inconsistent dimensions has a page size problem. A document that is fine on screen but too large to send has a file size problem.

A4, Letter, and what happens to the content

The two dominant standards are almost the same size and not quite compatible, which is the source of most resizing work. A4 is 210 × 297mm and is standard across Europe, Asia, and most of the world. Letter is 216 × 279mm and is standard in North America. Letter is 6mm wider and 18mm shorter — enough that a document laid out for one will not sit correctly on the other. Print an A4 document on Letter and the bottom of each page risks being clipped; print Letter on A4 and you get an uneven band of white at the foot.

How the content is handled is the decision that matters more than the dimensions. Scaling to fit resizes everything proportionally so nothing is lost, at the cost of slightly changing the size of the type — text set at 11pt may come out nearer 10.5pt going from Letter to A4. Keeping the content at its original size preserves the typography exactly but means the material sits on a differently shaped page, so margins become uneven and anything near an edge may fall outside the new boundary.

Two things are worth checking before you commit. Margins first: allow at least 12–15mm of clear space on all sides, because most office printers cannot print to the paper's edge and content placed nearer than that gets clipped regardless of page size. And documents that mix orientations — a landscape table among portrait pages — need looking at individually, since applying one page size uniformly can squash a wide table onto a narrow page.

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