How to use the PDF page resizer
- Drop a PDF onto the box or press Choose a file.
- Choose the Page size: A4, US Letter, US Legal, A3 or A5.
- Set a Margin in millimetres (0 to 100) if the content should stay clear of the edges, for example for printers that cannot print to the edge.
- Choose an Orientation: Match each page, Portrait or Landscape.
- Press Resize pages and download the result, named after the new size (
report-a4.pdf,report-letter.pdf).
What it does and when to use it
The most common need is moving between the North American and international paper sizes. A US Letter document printed on A4 paper, or an A4 one on Letter, gets clipped or shrunk unpredictably by the printer. Converting the PDF itself gives a predictable result and is often required by official portals, journals and print shops that specify A4. Other uses:
- Mixed scans. A file that combines receipts, Letter pages and A4 pages becomes one tidy size for printing or archiving.
- Enlarging. Print an A5 booklet page at A4 size for easier reading, or an A4 poster draft on A3.
- Adding a safe margin while keeping the paper size, which the PDF margin tool cannot do because it makes pages larger.
To see the current sizes, check the file with the PDF page counter or the PDF metadata viewer.
How it works
pdf-lib (@cantoo/pdf-lib) creates a new PDF in your browser with one sheet of the chosen size per original page. Each original page, as displayed (its visible area and rotation), is embedded as a vector drawing, scaled to the largest size that fits inside the margins, and centred. The document’s title, author and subject are copied to the new file. Nothing is uploaded and nothing extra is downloaded.
Scale = the smaller of (sheet width − 2 × margin) ÷ page width and (sheet height − 2 × margin) ÷ page height.
Worked examples
US Letter to A4, no margin. A 3-page Letter file (215.9 × 279.4 mm). The summary reads Every page placed on A4. The scale is 210 ÷ 215.9 ≈ 0.973, so the content fills the width at 210 × 271.8 mm with white bands of about 12.6 mm at the top and bottom.
A4 to US Letter with a 10 mm margin. The usable area is 195.9 × 259.4 mm. An A4 page is limited by the height, scaled to about 87%, and appears as 183.4 × 259.4 mm in the middle of the sheet.
A5 to A4. Each A5 page is enlarged about 1.41 times and fills an A4 sheet almost exactly.
Limits and tips
- Links, form fields, bookmarks and comments are not kept.
- Scanned pages that are enlarged will not gain detail.
- Password-protected files must be unlocked first with Unlock PDF.
Frequently asked questions
Is the content stretched to fill the new size?
Can it make pages bigger as well as smaller?
Why did my links stop working?
What does "Match each page" do?
How do we know nothing is uploaded? Test it yourself on the privacy proof page.