How do I convert a Letter PDF to A4?

Drop the file, choose A4, keep fit mode and download. Content scales by about 3% and centres with small top and bottom margins — the unavoidable consequence of A4 being narrower and taller than Letter.

Does resizing reduce PDF quality?

No. Pages are rescaled as vector transformations — text, lines and embedded images carry over at their original data. Nothing is re-rendered to pixels, so a 300-DPI-equivalent image stays exactly as sharp relative to the page.

What is the difference between fit and fill?

Fit scales content until it fits entirely inside the new page, adding margins where proportions differ — nothing is lost. Fill scales until the content covers the page completely, cropping whatever overflows. Documents usually want fit; edge-to-edge designs want fill.

Can I resize a document with mixed portrait and landscape pages?

Yes — each page is matched to the target size in its own orientation, so landscape pages become landscape A4 rather than being rotated or squeezed into portrait. The option can be disabled to force one orientation.

Why would I change a PDF's page size at all?

Submission systems and printers are strict about paper size: European institutions expect A4, US ones Letter, legal filings Legal. Mismatched sizes trigger auto-scaling at print time with unpredictable margins — resizing once, deliberately, keeps the layout under your control.

Resize PDF

Rescale every page of a PDF to A4, Letter, Legal, A3, A5 or Tabloid — content scaled and centred, text kept sharp, orientation preserved.

Resize PDF runs entirely in your browser. Your documents are processed on your device and never uploaded.

Open the Crop PDF tool

About Resize PDF

Resize PDF changes the paper size of every page — the classic case being a US Letter document that has to become A4 for European submission, or the reverse. Each page's content is scaled proportionally and centred on the new size: fit mode guarantees nothing is cut off, accepting slim margins where the shapes differ, while fill mode covers the page edge to edge and lets the overflow crop. Because the two formats differ in proportion (Letter is wider and shorter than A4), one of those trade-offs is unavoidable — the tool just makes it explicit and puts you in charge. Landscape pages automatically receive the landscape version of the target size, so mixed-orientation documents survive intact. Everything stays vector: text and line art are rescaled, not rasterised, and print quality is unchanged.

Features

Targets A4, US Letter, Legal, A3, A5 and Tabloid
Fit mode keeps all content; fill mode covers the full page
Content centred on the new page automatically
Per-page orientation matching for mixed documents
Detects and names the current page size, metric and imperial
Text and vectors stay sharp — no rasterisation
Whole document processed in one pass
Everything processed on your device

How to use the Resize PDF

Drop a PDF — its current page size is detected and named
Pick the target size
Choose fit (keep everything) or fill (cover the page)
Download the resized document

Example

Input

24-page US Letter report

Output

A4 pages, content scaled ×0.97 and centred, text still vector

Letter→A4 shrinks slightly in width; fit mode adds a few mm top and bottom.

Common errors & troubleshooting

Small margins appeared after converting Letter to A4. — Letter and A4 have different proportions, so fit mode must leave a sliver on one axis — that is geometry. Fill mode removes the margins by cropping a sliver instead; pick the trade-off you prefer.
An encrypted PDF will not open. — Password-protected files must be decrypted before their pages can be rewritten. Remove the password first, resize, then re-encrypt if needed.
Page numbers or headers sit closer to the edge than expected. — Everything scales together, including margins the original author left. Content near the page edge stays proportionally near the edge — check documents with tight margins in fill mode especially.
A print shop asked for bleed and crop marks after resizing. — Press-ready files with bleed zones need the resize done in the layout application so bleed is regenerated. This tool suits documents, reports and forms — not imposition-ready artwork.

Frequently asked questions

How do I convert a Letter PDF to A4?: Drop the file, choose A4, keep fit mode and download. Content scales by about 3% and centres with small top and bottom margins — the unavoidable consequence of A4 being narrower and taller than Letter.
Does resizing reduce PDF quality?: No. Pages are rescaled as vector transformations — text, lines and embedded images carry over at their original data. Nothing is re-rendered to pixels, so a 300-DPI-equivalent image stays exactly as sharp relative to the page.
What is the difference between fit and fill?: Fit scales content until it fits entirely inside the new page, adding margins where proportions differ — nothing is lost. Fill scales until the content covers the page completely, cropping whatever overflows. Documents usually want fit; edge-to-edge designs want fill.
Can I resize a document with mixed portrait and landscape pages?: Yes — each page is matched to the target size in its own orientation, so landscape pages become landscape A4 rather than being rotated or squeezed into portrait. The option can be disabled to force one orientation.
Why would I change a PDF's page size at all?: Submission systems and printers are strict about paper size: European institutions expect A4, US ones Letter, legal filings Legal. Mismatched sizes trigger auto-scaling at print time with unpredictable margins — resizing once, deliberately, keeps the layout under your control.

Related tools

Crop PDF — Trim margins from every page via the crop box.
Merge PDFs — Combine multiple PDFs into one, with reordering.
Split PDF — Extract pages or ranges (e.g. 1-3,5,7-9) into a new PDF.
Rotate PDF — Rotate all pages or a selection by 90/180/270°.
Compress PDF — Shrink a PDF by re-rendering each page to a JPEG at a chosen quality and resolution.
Organize PDF — Reorder, rotate and delete pages from thumbnails, then export.