How to resize a PDF file (page size or file size)

A coworker in Europe asks for your invoice on A4 paper, and yours is Letter. (On a phone? See how to resize a PDF on iPhone for print.) Or a portal says your upload is too big and tells you to resize it. Both people say resize, but they want different things. This guide covers both, starting with the page size.

What does it mean to resize a PDF?

Resizing a PDF usually means changing the page size, for example from A4 to Letter. People also use the phrase to mean making the file smaller in megabytes. These are two different jobs. Resize PDF changes the paper size. Compress PDF changes the file size.

How do I resize a PDF file to a new page size?

Add the file to Resize PDF, choose the page size you want, and save. The tool runs in your browser, so the document is not uploaded. Here are the steps.

1. Add your PDF. Drop it onto the tool or choose it from your device. The tool shows the size it has now, such as A4 (210 by 297 mm).
2. Choose the new size. Pick Letter, Legal, A4, A3, A5, A6 or Tabloid, or type your own width and height in inches or millimetres.
3. Choose the direction. Portrait makes every page tall, landscape makes every page wide, and as is keeps each page tall or wide the way it is now.
4. Add a margin if you want one. A margin keeps white space around the content on every side. Leave it at zero to use the whole page.
5. Press Resize PDF, look at the result, then download it. Your original file is not changed.

Which page size should I choose?

Pick the size of the paper the file will be printed on, or the size the person who asked for it uses. In the United States, letters and forms are usually Letter. Most other countries use A4. As of October 2026, Resize PDF offers these sizes:

• Letter: 8.5 by 11 inches.
• Legal: 8.5 by 14 inches.
• Tabloid: 11 by 17 inches.
• A4: 210 by 297 mm.
• A3: 297 by 420 mm.
• A5: 148 by 210 mm.
• A6: 105 by 148 mm.

You can also type any size you like, as long as the shorter side is at least one inch.

What happens to the content when the page size changes?

The content is scaled up or down by the same amount in both directions until it fits, then centered. Nothing is stretched. If the new page has a different shape, the leftover room becomes white space. Here are three worked examples, from the sizes listed above.

• Letter to A4: A4 is a little narrower but taller. The content shrinks by about 3 percent to fit the width, and you get about half an inch of white space above and below.
• A4 to Letter: Letter is wider but shorter. The content shrinks by about 6 percent to fit the height, and you get a strip of about a third of an inch down each side.
• Letter to Legal: both are 8.5 inches wide, so the content stays the same size. Legal is three inches taller, so you get an inch and a half of white space above and below.

These are rounded figures from simple arithmetic on the sizes. The result screen shows the old and the new size so you can check.

Will links and form fields still work after I resize a PDF?

Yes. Links, form fields and notes are moved and scaled along with the page, so they stay on the words and boxes they belong to. A jump target that points to an exact spot on a page, such as some bookmarks, still opens the right page but may land slightly off. Text stays text, so you can still select and search it.

What if I only want to trim the edges?

Resizing and cropping are not the same. Resizing scales everything onto a new page size. Cropping keeps the scale and shows only part of the page. To cut off wide scanner borders, use Crop PDF. To set the paper size afterwards, resize the cropped copy. If you work on a Mac, how to crop a PDF on a Mac covers that case.

How do I make a PDF file smaller instead?

If the real problem is a file that is too big to email or upload, changing the page size will not help much, because a page of the same pictures stays about the same weight. Use Compress PDF and read why your PDF is so big first, since the strongest setting turns text into pictures. Free files can be up to 50 MB. Pro allows up to 500 MB.

Common problems and fixes

• The printed page looks smaller than expected. Your print dialog may be shrinking the page a second time. Set it to actual size or 100 percent.
• The file has mixed page sizes. Choose a size and the direction as is. Every page lands on the same size, and each page keeps being tall or wide.
• The content touches the edge. Add a margin and run the resize again from your original file.
• You need only some pages at the new size. Resize PDF changes every page in the file. Pull out those pages with Extract PDF pages, resize that copy, and join it back with Merge PDF.

A short checklist

• Decide whether you need a new page size or a smaller file.
• Pick the size the paper or the other person uses.
• Choose as is unless every page should be the same direction.
• Check the result on the first and last page.
• Keep the original.

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