You've got a PDF that was made for A4 paper but your printer only handles US Letter — or the other way around. Or maybe you've merged files from different sources and now every page is a different size. Either way, you need to change the page size of a PDF, and you need to do it without paying for Acrobat Pro or uploading your document to a sketchy website.
Here's how to do it in under a minute, entirely in your browser.
How to change the page size of a PDF (3 steps)
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Open the PDF page size changer. No software to install — it runs in any modern browser.
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Upload your PDF. Drag and drop the file or click to browse. You'll see the current page dimensions and a list of standard size presets.
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Choose your target page size and download. Pick A4, US Letter, Legal, A3, A5, or enter custom dimensions. Choose whether to scale content to fit or just resize the canvas, then click Resize and download the result.
Your original file is never modified. The resized PDF downloads as a new file.
Which PDF page sizes are supported?
| Size | Dimensions | |------|-----------| | A4 | 210 × 297 mm (most of the world) | | US Letter | 216 × 279 mm (North America) | | US Legal | 216 × 356 mm | | A3 | 297 × 420 mm | | A5 | 148 × 210 mm | | US Tabloid | 279 × 432 mm | | Custom | Any width × height in points |
If you need a non-standard size — say, a specific envelope size or a custom print format — you can enter the exact dimensions manually.
Should you scale content or just resize the canvas?
This is the most important choice when changing PDF page size, and it trips people up.
Scale content to fit: The text, images, and layout are proportionally scaled to fill the new page size. Aspect ratio is preserved — nothing stretches. If you're converting from A4 to Letter (which are close in size but slightly different proportions), you may see very small margins appear, but the content will fill the page cleanly.
Resize canvas only (no scaling): The page dimensions change but the content stays at its original size and position. If you're making the page smaller, content may get cropped. If you're making it larger, white space appears around the edges. Use this option when you specifically want to add margin or frame the content.
For most conversions — like A4 to Letter or vice versa — scaling content to fit is the right choice.
The A4 vs Letter problem (and how to fix it)
This is by far the most common reason people need to change PDF page size.
A4 (210 × 297 mm) is the default paper size used in Europe, Asia, Australia, and most of the rest of the world. US Letter (8.5 × 11 inches / 216 × 279 mm) is slightly wider and noticeably shorter — used in the United States and Canada.
When an A4 PDF prints on Letter paper, you often get content cut off at the bottom, or awkward margins at the sides. Fixing it takes 30 seconds with a page size converter.
A4 is 7mm narrower but 18mm taller than Letter. When scaling to fit, the content shrinks very slightly to fit the shorter Letter height — barely noticeable in practice.
Changing page size for specific pages only
If you only need to change the size of certain pages (say, pages 1 and 5 in a 10-page document), the cleanest approach is:
- Use the PDF splitter to extract those specific pages
- Change the page size on the extracted pages
- Use the PDF merger to reassemble the document in the right order
It's a few extra steps but gives you precise control over which pages change size.
Does changing page size affect PDF quality?
No. Changing the page size is a structural operation — it adjusts the page dimensions in the PDF's internal format and optionally scales the content transform matrix. No images are re-encoded, no text is re-rendered. Quality stays exactly the same.
The one exception is if you scale content to fit a dramatically different page size (say, A5 to A0). At that scale difference, you'd see the same quality you'd see printing a small image very large — because the underlying image pixels haven't changed, just their display dimensions.
For standard conversions (A4 ↔ Letter ↔ Legal), quality is indistinguishable from the original.
Changing PDF page size vs. scaling vs. cropping
These three operations are often confused:
- Change page size: The canvas gets bigger or smaller. Use this to match a specific paper format.
- Scale content: The content gets bigger or smaller. Usually done within a page size change.
- Crop: Trims visible area without changing how the content is laid out. Use the crop PDF tool for this.
If you want to print a landscape PDF on portrait paper by making the content fit: change the page size with scale-to-fit. If you want to trim white borders: crop. If you want to make everything bigger without changing the page: scale.
Common workflows
Making a PDF print correctly at the office
Your PDF came from someone in Europe (A4), but your office printer defaults to Letter. Open the page size changer, convert to Letter with scale-to-fit, and the document will print cleanly on every printer in your office.
Preparing a PDF for professional printing
Print shops often specify exact page sizes and bleed requirements. If your PDF is Letter but the printer wants A4 with 3mm bleed: resize to A4, then use a PDF editor to add the bleed area. The page size change is the first step.
Standardizing a merged document
You've merged 10 PDFs from different sources — some are A4, some Letter, some portrait, some landscape. Run all pages through the page size changer with a fixed target size to get a uniform document.
Frequently asked questions
Is there a limit on file size or page count?
No hard limit. Processing happens entirely in your browser, so the practical limit is your device's available memory. Documents up to a few hundred pages work fine on any modern laptop or desktop.
Will the fonts and text stay sharp after resizing?
Yes. PDF text is vector-based, so it scales perfectly regardless of how much you resize. Raster images in the PDF scale at their embedded resolution — they won't get sharper if you make the page bigger, but standard conversions between similar sizes (A4/Letter) won't cause any visible quality loss.
Can I change page size on a scanned PDF?
Yes. Scanned PDFs are image-based, but the page size change still works — it resizes the page canvas and scales the scanned image to fit. The image itself won't become higher resolution, but the page dimensions will match your target size.
Is my PDF uploaded to a server?
No. The PDF page size changer processes your file entirely in your browser using JavaScript. Your document never leaves your device. This makes it safe to use with confidential documents — contracts, medical records, legal filings.
Can I undo the page size change?
Since your original file is never modified, you can always re-open the original and start over. The resized version is a separate download. Keep both if you might need either.