Change PDF Page Size to A4, Letter, A5 or a Custom Dimension

About the PDF Resize Tool

Choose a target from A4, US Letter or A5, or select Custom and type an exact width and height in points — the field appears only when you need it, and accepts anything from 72 points upwards. Every page in the document is then placed onto a page of that size, scaled by whichever dimension runs out first and centred in both directions, so nothing is ever cropped and nothing is distorted.

This matters most when a document is crossing between paper standards. US Letter is 612 by 792 points and A4 is 595.28 by 841.89 — wider but shorter — which is why a Letter document printed on A4 in Europe loses a strip off the bottom, and an A4 document printed on Letter in North America loses the edges. Resizing the file properly fixes it once, rather than relying on every person who opens it to remember the right print setting.

Key Features

• Three presets plus exact control: A4, US Letter and A5 are one click; Custom exposes width and height fields in points for trim sizes that are not a standard paper format.
• Content is never cropped: The scale factor is the smaller of the two ratios, so the whole page always fits inside the new dimensions with margin to spare on one axis.
• Centred on both axes: Remaining space is split evenly rather than pushed to one corner, which keeps a resized document looking deliberate.
• Text layer survives: Pages are embedded as vector content rather than rendered to images, so the finished PDF stays searchable and its text selectable.
• Opens restricted files: Documents carrying an owner password that blocks editing are loaded with encryption ignored, so a locked-down file can still be resized.
• Points, not guesses: Custom sizing works in the PDF's own unit — 72 points to the inch — so a 5 by 8 inch book block is 360 by 576 and needs no conversion table.

How to Use the PDF Resize Tool

1. Add the PDF whose pages you want resized.
2. Pick A4, US Letter or A5 — or choose Custom and enter the width and height in points.
3. Press Resize Pages.
4. Download the result, saved with -resized appended to the original filename.

How It Works

pdf-lib loads the source, embeds each existing page as a reusable object, and draws it onto a newly created page of the target dimensions. Because the page content is embedded rather than rasterised, the output keeps its vector graphics, its fonts and its selectable text at full fidelity — unlike the grayscale converter, this tool does not degrade anything.

Two behaviours follow from the embedding approach and are worth knowing in advance. First, annotations, form fields and link areas are not carried across: what gets embedded is the visible page content, so an interactive form comes back as a picture-perfect but non-fillable version of itself. Second, the target size is applied to every page uniformly. A document mixing portrait text pages with landscape charts will have the landscape pages shrunk to fit the portrait width, leaving white bands above and below them.

When You Need It

An author self-publishing a paperback has a manuscript exported at A4 and a printer demanding a 5.5 by 8.5 inch trim. Custom sizing at 396 by 612 points reformats the whole block in one pass. Unpublished manuscripts are exactly the kind of file authors are warned not to scatter across free web services, and here the file never goes anywhere to be reformatted.

An engineering office in Germany regularly receives specifications and drawings from American clients on US Letter, and the plan printer downstairs is loaded with A4. Converting on receipt saves a daily argument with the print dialog. The drawings are covered by supplier confidentiality agreements, so a conversion that happens inside the browser avoids the awkward question of which jurisdiction a conversion service's servers sit in — a question that has a specific and unwelcome answer under German data protection rules.