A document written in the US is on Letter paper; the printer in your office, and every portal in Europe, expects A4. A scan came out as A3 and a form says "A4 only". A brochure needs to be A5. Resize PDF changes the page size of a whole document and scales the content to fit, so you don't have to re-export from the original program, which you may not even have.
How to change a PDF's page size
- Open your PDF.
- Choose the new size: A4, A3, A5, US Letter, US Legal, Tabloid, or enter your own in millimeters.
- Choose the orientation: Match each page keeps portrait pages portrait and landscape pages landscape; or force everything to one orientation.
- Choose scaling: Fit inside shows everything, with white bars if the shapes differ; Fill the page covers the whole sheet but may cut off the edges.
- Add a margin if you like, then click Resize & download.
A4 versus Letter: why it matters
A4 (210 × 297 mm) is used almost everywhere except North America, where US Letter (8.5 × 11 inches, 216 × 279 mm) rules. Letter is shorter and slightly wider. A document made for one prints awkwardly on the other: text near the bottom can be cut off, or there's an odd margin. Converting properly, with the content scaled to fit, avoids both problems. It's especially useful when working across the Atlantic, such as a US contract that has to be filed in a European office.
Fit or fill?
Fit inside is the safe choice: every bit of the original page is visible, and if the proportions differ you get some extra white space at the top and bottom or at the sides. Fill the page scales the content until it covers the whole new page, which looks better for photos and full-bleed designs but can crop the edges, so check that nothing important sits near the margin. For text documents, always use Fit.
A worked example
You've been sent a 10-page proposal in US Letter and the client's printer is set up for A4. Open the PDF, choose A4, keep "Match each page" and "Fit inside", and click download. The pages are made slightly taller, the content is scaled by about 98%, and you get a clean A4 file with the text still sharp and selectable. The whole conversion takes seconds and nothing was uploaded.
It keeps text sharp
Pages are placed onto the new page as vector content, not turned into pictures, so there's no loss of quality. That's different from a "print to PDF" trick, which often rasterizes pages and makes them blurry. Fonts, links and searchable text stay as they were. Pages that were stored sideways are handled correctly too, so a landscape table stays the right way up on its new page.
Combine with other tools
- Crop first if there's a dark scanner border: Crop PDF removes it, then resize.
- Save paper after resizing by printing several pages on one sheet with Multiple Pages per Sheet.
- Make the file smaller. Oversize scans are often much heavier than they need to be; resize to A4 and then compress.
- Mixed sizes? A merged file may contain A4, Letter and landscape pages; resize unifies them, and then page numbers sit consistently.
- Fix sideways pages with Rotate PDF before choosing the orientation.
Margins and printing
Most office printers can't print the last 4 to 5 mm at the edge of a sheet. If you're resizing for print, add a margin of 5 mm or more so nothing gets cut off. For a binder, a bigger margin on the side is worth it. If a document is meant for a small format such as A5, check that the text is still readable after scaling; shrinking an A4 page to A5 reduces everything to about 70% of its original size, so small print can become hard to read.
The conversion happens in your browser, and the PDF is not uploaded, which is helpful for contracts and other private files. Password-protected PDFs must be unlocked first, and very large files may need a moment to process.
Troubleshooting
If the text looks smaller after resizing, that's expected when going from a larger to a smaller format, such as A4 to A5; the whole page is scaled. If you see wide white bars, the proportions of the original differ from the new size; switch to Fill, or choose a size that matches better. If pages come out in the wrong orientation, set the orientation explicitly instead of Match each page. And if the document is mostly pictures, check the result at full size before you print.
Paper sizes at a glance
A3 is 297 × 420 mm, A4 is 210 × 297 mm and A5 is 148 × 210 mm; each is half the area of the one before. US Letter is 8.5 × 11 in, Legal is 8.5 × 14 in and Tabloid is 11 × 17 in. If you're printing for someone in another country, ask which size their printer uses. Sending the right size from the start avoids shrunken text and odd margins.