How is this different from other online PDF tools?

Most online PDF tools send your files to a remote server for processing. This tool processes everything locally in your browser using client-side JavaScript. Your files are never transmitted to any server, which means your document content stays entirely under your control.

Are my PDF files uploaded?

No. Your files are read directly by your browser. Your files are never transmitted over the network. The tool works entirely within the browser tab you have open.

Can I verify that files are not uploaded?

Yes. Open your browser's developer tools (F12), go to the Network tab, and watch for any outgoing requests while using the tool. You will see no file data leave your browser. The site may record an anonymous page-view count, which never includes your files and can be disabled.

Does this tool work offline?

Yes, once the page has loaded the tool processes your files entirely in your browser; tool functionality needs no network connection. You can disconnect from the internet and continue using it.

What happens when I refresh the page?

Because nothing is stored on a server, refreshing the page clears your current session. Any files you had selected will need to be selected again.

Does this tool store my files?

No. Files are held in browser memory only for as long as the page is open. Closing or refreshing the page discards them. Nothing is written to disk by the tool, and nothing is sent to a server.

Can this tool unlock password-protected PDFs?

No. This tool does not attempt to remove or bypass PDF password protection. If you know the password, the Unlock PDF tool on this site can remove it locally; then this tool can process the file.

What technologies does this tool use?

This tool uses client-side JavaScript and pdf-lib to embed each page and scale it onto a standard A4 or Letter page entirely within your browser — your files never leave your browser.

Does this tool use WebAssembly?

No. This tool uses client-side JavaScript and pdf-lib for local PDF structure editing. No WebAssembly is involved.

How do I resize a PDF to A4 or Letter?

Pick a PDF with the file picker, choose A4 or US Letter and an orientation (Auto, Portrait, or Landscape), then select Resize and save the result. Everything runs locally in your browser, so the file never leaves your device.

Why does my resized page have blank margins on two sides?

Each page is scaled to fit the target size while keeping its original aspect ratio, then centred, so a page whose proportions differ from A4 or Letter gets even margins on the two sides where it does not fill the sheet. This avoids stretching or cropping your content.

What does the Auto orientation option do, and what happens to mixed page sizes?

Auto matches each page to its own visual orientation, so a landscape page becomes landscape A4 or Letter and a portrait page becomes portrait, which is handy for documents with mixed page sizes. Picking Portrait or Landscape instead forces every page to that orientation regardless of the source.

Does it cost anything to use the Resize PDF (A4 / Letter) tool?

Resize PDF (A4 / Letter) is completely free — no account, no sign-up, and no cap on how many PDFs you resize, and it always will be. Every page is scaled to your chosen paper size entirely inside your browser using pdf-lib, so your file is never sent to a server or seen by anyone else.

Resize a PDF to A4 or Letter Privately — Normalise Page Sizes in Your Browser

Select a PDF, choose A4 or US Letter and an orientation, and download a copy with every page scaled to that size — all locally in your browser.

Quick answer

What it does: Select a PDF, choose A4 or US Letter and an orientation, and download a copy with every page scaled to that size — all locally in your browser.
Free?: Yes — 100% free, no account or sign-up.
Files uploaded?: No — everything is processed in your browser.
Works offline?: Yes — once the page has loaded.
Best for: A student normalises a mixed batch of A4 and Letter lecture slides into a consistent A4 PDF before printing.
Good to know: Content is scaled to fit, so pages with a different aspect ratio than the target will have margins on two sides.

How it works

Select a PDF file from your device using the file picker.
The file is read into browser memory — no data leaves your browser.
Choose the target size (A4 or US Letter) and an orientation (Auto, Portrait, or Landscape).
pdf-lib scales each page's content to fit the target size, preserving aspect ratio and centring it.
The resized PDF is offered as a download directly from your browser.

When to use this tool

A student normalises a mixed batch of A4 and Letter lecture slides into a consistent A4 PDF before printing.
A designer scales a custom-size brochure down to US Letter for a client who needs to print it locally.
A small business standardises invoices received in various sizes to A4 before archiving them.
Content is scaled to fit, so pages with a different aspect ratio than A4/Letter will have blank margins on two sides; interactive form fields may not carry over.

Frequently asked questions

How is this different from other online PDF tools?: Most online PDF tools send your files to a remote server for processing. This tool processes everything locally in your browser using client-side JavaScript. Your files are never transmitted to any server, which means your document content stays entirely under your control.
Are my PDF files uploaded?: No. Your files are read directly by your browser. Your files are never transmitted over the network. The tool works entirely within the browser tab you have open.
Can I verify that files are not uploaded?: Yes. Open your browser's developer tools (F12), go to the Network tab, and watch for any outgoing requests while using the tool. You will see no file data leave your browser. The site may record an anonymous page-view count, which never includes your files and can be disabled.
Does this tool work offline?: Yes, once the page has loaded the tool processes your files entirely in your browser; tool functionality needs no network connection. You can disconnect from the internet and continue using it.
What happens when I refresh the page?: Because nothing is stored on a server, refreshing the page clears your current session. Any files you had selected will need to be selected again.
Does this tool store my files?: No. Files are held in browser memory only for as long as the page is open. Closing or refreshing the page discards them. Nothing is written to disk by the tool, and nothing is sent to a server.
Can this tool unlock password-protected PDFs?: No. This tool does not attempt to remove or bypass PDF password protection. If you know the password, the Unlock PDF tool on this site can remove it locally; then this tool can process the file.
What technologies does this tool use?: This tool uses client-side JavaScript and pdf-lib to embed each page and scale it onto a standard A4 or Letter page entirely within your browser — your files never leave your browser.
Does this tool use WebAssembly?: No. This tool uses client-side JavaScript and pdf-lib for local PDF structure editing. No WebAssembly is involved.
How do I resize a PDF to A4 or Letter?: Pick a PDF with the file picker, choose A4 or US Letter and an orientation (Auto, Portrait, or Landscape), then select Resize and save the result. Everything runs locally in your browser, so the file never leaves your device.
Why does my resized page have blank margins on two sides?: Each page is scaled to fit the target size while keeping its original aspect ratio, then centred, so a page whose proportions differ from A4 or Letter gets even margins on the two sides where it does not fill the sheet. This avoids stretching or cropping your content.
What does the Auto orientation option do, and what happens to mixed page sizes?: Auto matches each page to its own visual orientation, so a landscape page becomes landscape A4 or Letter and a portrait page becomes portrait, which is handy for documents with mixed page sizes. Picking Portrait or Landscape instead forces every page to that orientation regardless of the source.
Does it cost anything to use the Resize PDF (A4 / Letter) tool?: Resize PDF (A4 / Letter) is completely free — no account, no sign-up, and no cap on how many PDFs you resize, and it always will be. Every page is scaled to your chosen paper size entirely inside your browser using pdf-lib, so your file is never sent to a server or seen by anyone else.