Resizing a PDF page — changing it from A4 to Letter, from Letter to A3, or to a custom dimension — comes up when documents need to fit a specific format for printing, submission, or display. The operation changes the page dimensions but what happens to the content inside depends on which approach you use.
Two Different Things People Mean by "Resize a PDF"
Before choosing a method, clarify what you actually need:
- Change the page dimensions and scale the content to fit: the page gets larger or smaller, and the content scales with it. Everything stays proportional — text, images, and layout all resize together. The document looks the same but at a different physical size.
- Change the page dimensions without scaling the content: the page canvas changes size but the content stays at its original size. This adds white space around content (when making the page larger) or crops content (when making the page smaller).
Most people want the first option — resize page and scale content together. The second option is useful for specific cases like adding margins around content or cropping to remove unnecessary white space.
The Print Dialog: Simplest Resize Method
The print dialog in any PDF viewer can resize and reformat a PDF when saving to a new PDF:
- Open the PDF and press Ctrl+P (Windows) or Cmd+P (Mac)
- Select Save as PDF or Microsoft Print to PDF as the printer
- Change the paper size to the target dimensions — Letter, A4, A3, or custom
- Select "Fit" or "Scale to fit" in the scaling options — this scales the content to fill the new page size
- Save — the new PDF has the content scaled to the target page size
This method works in any application and requires no additional software. The tradeoff is that it goes through the print renderer, which may not perfectly preserve all document features. For basic resizing it's reliable and fast.
Adobe Acrobat Pro: More Control
Acrobat Pro gives more precise control over page resizing through two tools:
- Print Production > Set Page Boxes: changes the page dimensions without scaling content. Use this to add white space around content (make page larger) or remove margins (make page smaller). Good for adjusting crop boxes and media boxes precisely.
- Print to PDF with scaling: print from within Acrobat with a different page size and the "Fit" scaling option. This scales content and changes the page size simultaneously, similar to the print dialog method but with more control over scaling percentage.
Common Conversions and What to Expect
- A4 to Letter: A4 (210×297mm) is slightly taller and narrower than Letter (216×279mm). Scaling A4 content to Letter crops or squishes it slightly. For most text documents the difference is negligible. For precisely formatted documents, check the result carefully.
- Letter to A4: the same issue in reverse. The proportions differ slightly. Most documents survive the conversion without noticeable issues.
- Scaling up (A4 to A3): content scales up proportionally. Digital text remains sharp (it's resolution-independent). Raster images may show pixelation at double size — PDF Quality depends on the original image resolution.
- Scaling down (A3 to A4): content reduces proportionally. Small text may become harder to read. Check that the smallest text in the document is still legible at the reduced size.
When to Resize in the Source Document Instead
For documents where the layout was carefully designed for a specific page size — reports with precise column widths, forms with exact field positions, marketing materials with specific print specifications — resizing the PDF often produces imperfect results. Text reflows unexpectedly, margins change, and design elements shift. For these documents, the right approach is to return to the source file, change the page size there, reformat as needed, and re-export. Resize in the PDF only when the source isn't available or the document is simple enough that scaling produces an acceptable result.