PDF Resizer
Resize Settings
Drop your PDF here, or click to browse
Accepts .pdf files — processed entirely in your browser
Scale content proportionally to fit within the new page — no cropping, slight margins if aspect ratios differ.
Upload a PDF to Get Started
Select a .pdf file, choose your target page size and options, then click Resize PDF. The resized file downloads directly to your device — no upload, no waiting.
Change PDF page dimensions instantly — 100% private, no file upload
Changing the page size of a PDF document is one of the most common document-preparation tasks in any office or home workflow. Whether you need to convert a US Letter document to A4 for international printing, shrink a large A3 drawing to A5 for distribution, or apply a completely custom dimension for a unique project, a PDF resizer removes the need for expensive desktop software. Our PDF Resizer tool runs entirely inside your web browser using the open-source pdf-lib library. Your file never leaves your device — it is never uploaded to any server, never stored in the cloud, and never seen by any third party. This privacy-first approach is a genuine differentiator: every major competitor (Sejda, PDF24, PDF2Go, PDFResizer.com) requires your file to be uploaded to their servers, where it sits for up to two hours before deletion. With our tool, the moment you close the browser tab, every trace of your file is gone. Beyond privacy, our tool covers the full range of use cases professionals and home users encounter every day. You can resize a single page or the entire document in one pass. When the target page is a different aspect ratio from the original — say, converting a square graphic to A4 — you choose exactly how the content should be handled: the Fit mode scales the content proportionally so nothing is cropped, leaving thin margins on the sides if needed; the Fill mode scales to cover the full target page, cropping slightly if the aspect ratios differ; and the None mode leaves the content at its original size and simply centers it on the new canvas, useful when you want to place a small graphic onto a larger blank page. All three modes respect the orientation setting — Portrait, Landscape, or Auto-detect, which preserves whatever orientation each original page already has. The tool supports the most important standard page sizes used around the world: A4 (210 × 297 mm), A3 (297 × 420 mm), A5 (148 × 210 mm), A6 (105 × 148 mm), US Letter (8.5 × 11 in), US Legal (8.5 × 14 in), Ledger (17 × 11 in), Tabloid (11 × 17 in), and Executive (7.25 × 10.5 in). For anything outside this list, the Custom option lets you type any width and height in either millimetres or inches. The quick-preset chips across the top of the size section let you jump to the five most common sizes in a single tap — ideal on mobile, where switching between a dropdown and a toggle can feel slow. For multi-page documents, you can apply the resize to all pages at once, or restrict it to a specific page range using the compact range notation (for example, 1-3, 5, 8-10). Pages outside the range are copied into the output unchanged, so the output file is always a complete document with the same page count as the original. Once processing is complete — which typically takes one to three seconds even for large documents — the results panel shows the original versus new page dimensions displayed in your chosen unit, a visual bar chart that lets you compare the relative page areas at a glance, the before and after file sizes in kilobytes, and a Download button that saves the resized PDF directly to your computer. Because everything happens in your browser, there is no waiting for a server queue and no file-size limit imposed by a free tier.
Understanding PDF Page Resizing
What Is PDF Page Resizing?
A PDF file describes each page using a MediaBox, which is a rectangle that defines the visible area of the page in PDF points (one point equals 1/72 of an inch). Resizing a PDF page means replacing this MediaBox with a new one that has different width and height values, then repositioning or rescaling the page's existing content so that it fits properly within the new canvas. Unlike rasterizing an image, PDF resizing can preserve vector text and graphics at full quality because it works with the document's native drawing instructions rather than pixel values. The result is a PDF whose pages display and print at the new dimensions, matching the output requirements of a different printer, document template, or publishing workflow.
How Are Dimensions and Scaling Calculated?
Standard page sizes are defined in points. A4 is 595.28 × 841.89 pt, US Letter is 612 × 792 pt, and so on. When you select a unit (mm or inches), the tool converts your input to points before processing. For Fit mode, the tool computes scaleX = targetWidth / originalWidth and scaleY = targetHeight / originalHeight, then takes the smaller of the two (scale = Math.min(scaleX, scaleY)) so that the content shrinks or grows uniformly without exceeding the target boundary. The content is then centered on the new page using offsetX = (targetWidth - originalWidth × scale) / 2 and a matching vertical offset. Fill mode uses Math.max instead so the content always covers the full target area, which may crop a sliver of content on the shorter axis. None mode skips scaling entirely and simply centers the original content on the new canvas.
Why Does Page Size Matter?
Mismatched page sizes are a common source of printing waste, clipped content, and unprofessional-looking documents. A contract prepared on US Letter will show white borders or cropped text when printed on A4 in Europe. A poster designed at A3 may not display correctly when embedded in a presentation built for A4 slides. Converting PDFs to a consistent size before distributing them ensures they render predictably across different printers, e-readers, and PDF viewers. Page size also affects the displayed file size in some PDF viewers and the print dialog experience for end users. Standardising on A4 or Letter is often a company-wide or client requirement, and the ability to do this conversion instantly in the browser — without installing Acrobat or relying on a server-side tool — saves significant time.
Limitations to Be Aware Of
While client-side PDF resizing with pdf-lib works well for the vast majority of documents, there are some edge cases to know. Password-protected or encrypted PDFs cannot be processed unless you first remove the password using a separate tool. Some older PDF files use non-standard encoding or contain external font references that pdf-lib may not fully resolve, which can result in minor visual artefacts in the output. The None (no-scale) mode may place content partially outside the visible page area if the original content is significantly larger than the target canvas — in this case, Fit mode is recommended. Very large PDFs (hundreds of pages or very high-resolution embedded images) may require several seconds to process and use meaningful browser memory; for files over roughly 50 MB, processing time will be noticeable.
How to Resize a PDF
Upload Your PDF
Click the upload area or drag and drop your PDF file into it. The file is loaded directly into your browser — it is never sent to a server, so your document stays private.
Choose Target Size and Orientation
Tap one of the quick-preset chips (A4, Letter, A5, A3, Legal) or use the dropdown to select from nine standard sizes, or enter a custom width and height. Choose Portrait, Landscape, or Auto-detect orientation.
Set Content Scaling and Page Range
Select Fit to scale content proportionally without cropping, Fill to cover the full page area, or None to keep the original size and center it. Optionally restrict processing to a specific page range (e.g. 1-3, 5).
Resize and Download
Click Resize PDF. Processing typically completes in one to three seconds. Review the dimension and size comparison in the results panel, then click Download Resized PDF to save the file directly to your device.
Frequently Asked Questions
Is my PDF uploaded to a server?
No — your file never leaves your device. This tool uses the open-source pdf-lib library, which runs entirely inside your web browser. The file is read from your local disk into browser memory, processed using JavaScript, and the output is offered as a direct download. No data is transmitted over the internet at any point. This is fundamentally different from server-based tools like Sejda, PDF24, or PDF2Go, where your file is uploaded to a remote server and queued for processing. If privacy is a concern — for legal documents, financial reports, or personal files — this tool is the safest option available.
What is the difference between Fit, Fill, and None scaling?
These three modes control how existing page content is handled when the target page has different dimensions or a different aspect ratio. Fit scales the content proportionally so that it fits entirely within the new page — nothing is cropped, but there may be small blank margins on two sides if the aspect ratios differ. Fill scales proportionally to cover the entire new page, which may crop a small strip on the shorter axis. None keeps the content at its exact original size and simply centers it on the new canvas; this is most useful when you are placing a small document onto a larger blank page to add whitespace around it.
Can I resize only specific pages in a multi-page PDF?
Yes. Toggle the Apply To setting to Page Range, then enter your pages using the standard range notation: individual page numbers separated by commas (e.g. 1, 3, 7), ranges with a hyphen (e.g. 2-5), or combinations (e.g. 1-3, 5, 8-10). Pages outside the specified range are copied into the output document without modification, so the page count of the output file always matches the original. This is useful when only certain pages need a different paper size — for example, a cover page in Letter format in an otherwise A4 document.
What standard page sizes are supported?
The tool supports nine of the most widely used international and North American page sizes: A4 (210 × 297 mm), A3 (297 × 420 mm), A5 (148 × 210 mm), A6 (105 × 148 mm), US Letter (8.5 × 11 in), US Legal (8.5 × 14 in), Ledger (17 × 11 in), Tabloid (11 × 17 in), and Executive (7.25 × 10.5 in). If you need a size not on this list, select Custom and enter any width and height in millimetres or inches. All values are converted internally to PDF points (1 pt = 1/72 inch) before processing.
Why is my output file larger than the original?
When this tool resizes a PDF, it embeds the original pages as PDF XObjects (essentially page templates) inside a newly created document structure. This wrapping can slightly increase the raw file size, particularly for short documents or documents with already-compressed content. The output PDF is a fully valid, standards-compliant document. If file size is a priority after resizing, you can run the output through a PDF compression tool as a second step. For most use cases — printing, email attachment, archiving — the size difference is minimal and the quality is identical to the source.
Can I resize encrypted or password-protected PDFs?
Not directly. If a PDF has an owner password (which restricts copying, printing, or editing) or a user password (which locks viewing), pdf-lib will be unable to open it and the tool will display an error. To process such a file, you first need to remove the password protection using a PDF decryption tool, save an unlocked copy, and then use the unlocked copy with this resizer. Note that removing a password from a PDF you do not own or have authorisation to modify may violate copyright or data-protection laws in your jurisdiction.