How to Resize PDF Pages Between A4, Letter, and Legal

You’ve got a PDF formatted for A4 and you need to print it on a US Letter printer, or vice versa — and the sizes are close enough that people assume it’ll “just work,” until margins come out wrong or content gets cropped at the edges. A4 and Letter aren’t the same dimensions, and a document that fits perfectly on one doesn’t automatically fit the other without some kind of resizing step.

This comes up constantly in international collaboration — a template built by someone in a Letter-standard country, shared with someone in an A4-standard one, and neither party realizes there’s a mismatch until the print job comes out wrong.

What resizing PDF pages actually involves

Converting a PDF’s page size means changing the dimensions of every page to a new target size — A4, Letter, Legal, A3, A5, or Tabloid, most commonly — while deciding what happens to the content that doesn’t map perfectly between the old and new dimensions. Content can either be scaled proportionally to fit within the new page size (preserving aspect ratio but potentially leaving margins, or requiring the content to shrink slightly) or stretched to fill the new dimensions exactly (filling the whole page but distorting the original aspect ratio slightly).

Since A4 and Letter have meaningfully different aspect ratios (A4 is narrower and taller relative to its width than Letter), stretching to fit exactly will introduce a small but real distortion, while scaling to preserve aspect ratio will leave some margin difference instead. Neither is “wrong” — they’re different trade-offs depending on whether visual accuracy or exact fit matters more for your specific document.

Why people get stuck here

• A4 and Letter look similar but aren’t identical. The size difference is small enough to be easy to ignore and large enough to cause real print margin problems.
• Scaling vs. stretching trade-offs aren’t obvious upfront. People often don’t realize there’s a choice to make between preserving proportions and filling the page exactly until they see an unexpected result.
• International templates get shared without size adjustment. A document built for one region’s standard paper size doesn’t automatically resize itself when opened somewhere using a different standard.
• Print jobs fail silently on size mismatches. Some printers auto-scale to compensate for a size mismatch, others crop or leave unexpected margins, and the specific behavior isn’t always predictable in advance.

What a good PDF page size converter looks like

Supports the common target sizes

A4, Letter, Legal, A3, A5, and Tabloid cover the vast majority of real-world page size needs across regions and use cases.

Offers both scale and stretch options

Since the right choice depends on the specific document and how much aspect-ratio distortion is acceptable, having both options available matters.

Applies consistently across every page

A multi-page document should have every page resized the same way, keeping the document visually consistent throughout.

Common mistakes to avoid

• Assuming A4 and Letter are close enough to be interchangeable without any resizing step.
• Choosing stretch-to-fit for a document with important visual proportions (a diagram, a photo) where a small distortion would actually be noticeable.
• Not checking the resized result before sending a large batch of documents to print.
• Forgetting that resizing a PDF page doesn’t change its actual text content — it’s a page dimension adjustment, not a re-flow of text into a new layout.

How to do it with the PDF Page Size Converter

Online Tool Store’s PDF Page Size Converter resizes every page in a PDF entirely in your browser.

1. Upload your PDF.
2. Choose your target page size — A4, Letter, Legal, A3, A5, or Tabloid.
3. Choose whether to scale (preserving proportions) or stretch (filling exactly) to the new size.
4. Download the resized PDF.

Because the conversion runs locally, your document doesn’t need to be uploaded to a third-party server just to change its page dimensions.

Frequently asked questions

What’s the actual size difference between A4 and Letter?

A4 measures 210 × 297 mm (about 8.27 × 11.69 inches), while US Letter measures 8.5 × 11 inches (215.9 × 279.4 mm) — A4 is narrower and taller, Letter is wider and shorter. The difference is small but enough to cause margin or cropping issues if a document isn’t resized appropriately for the target size.

Should I scale or stretch when converting page size?

Scale (preserving aspect ratio) is usually the safer default for documents where visual proportions matter — diagrams, photos, precisely laid-out content. Stretch (filling the new page exactly) can work fine for simpler text documents where a very slight distortion won’t be noticeable or matters less than an exact fit.

Does resizing a PDF page change the text content or just the page dimensions?

Just the page dimensions and how the existing content is scaled or stretched to fit them — it’s not re-flowing or re-formatting text into a new layout, so very dense content on a smaller target size might still look cramped even after resizing.

Final thought

A4 and Letter are close enough to trick people into skipping the resize step, and different enough that skipping it shows up as a real, visible problem the moment the document actually gets printed.

Try the free PDF Page Size Converter