How to Resize PDF Pages: Change Dimensions to A4, Letter, or Custom Sizes

PDF page sizes are defined in points (1 point = 1/72 inch). Common sizes in points: A4 is 595 × 842 pt, US Letter is 612 × 792 pt, A3 is 842 × 1191 pt, and Legal is 612 × 1008 pt. When a PDF viewer or printer receives a PDF, it renders each page at the dimensions specified in the file — it does not automatically scale to fit the paper unless you tell it to. This is why a PDF designed for US Letter looks slightly different when printed on A4 — the aspect ratios differ (Letter is wider relative to its height). Professional print shops require exact dimensions, which is why resizing to the correct standard before submission matters. For digital-only use, the page size affects how the document appears in viewers and on e-readers.

The simplest free method to resize PDF pages is through your browser's print dialog. This re-renders the PDF at a new page size and saves the result as a new PDF file. It works for most text-based and image-based PDFs and requires no additional software beyond a modern browser. This approach scales content to fit the new dimensions while maintaining aspect ratios. If the source and target have different aspect ratios (like Letter to A4), there will be a small amount of padding or slight scaling. For most practical purposes, this is indistinguishable from a purpose-built resize.

1. 1Open your PDF in Chrome or Firefox by dragging it into a browser tab.
2. 2Press Ctrl+P (Windows) or Cmd+P (Mac) to open the print dialog.
3. 3Set the destination to 'Save as PDF' and select your desired paper size (A4, Letter, Legal, etc.).
4. 4Enable 'Fit to page' or 'Scale to fit' if available, then click Save to download the resized PDF.

If you have a multi-page PDF with inconsistent page sizes — common with scanned documents or assembled from multiple sources — the best approach is to first organize the pages using LazyPDF's Organize tool, then apply a uniform resize via the print method. For documents where you want to add white padding rather than scale content (to reach a larger canvas without shrinking the content), you would need a more advanced PDF editing tool. However, for the common case of scaling down (e.g., A3 to A4 or US Letter to A4), the browser print method is entirely adequate and produces clean results. After resizing, run the file through LazyPDF's Compress tool to optimize the re-rendered PDF and reduce any size bloat from the re-processing step. Ghostscript compression typically reduces the output size by 20–40% compared to browser-generated PDFs.

LazyPDF's Compress tool is ideal when you want to resize pages as part of a broader optimization step. Ghostscript, which powers the compression, allows page scaling as a parameter, and the compression process naturally re-renders all pages at the target output quality. The result is a resized, compressed, and flattened PDF in a single pass. LazyPDF's Organize tool is useful when the resizing task is really about fixing page orientation or removing blank pages that affect the perceived size of the document. For example, if pages are landscape when they should be portrait (or vice versa), Organize lets you remove those incorrectly oriented pages before reassembling. For true dimension changes (MediaBox resizing), the browser print method remains the most accessible option without dedicated software. Combining it with LazyPDF's compression as a second step gives you the best quality-to-size ratio.

Different use cases call for different resizing strategies. For e-reader optimization, you want to remove margins and resize to the exact screen resolution of your device — common targets are 6-inch (1448 × 1072 px at 300 DPI) or 7-inch e-reader screens. The browser print method lets you specify custom paper dimensions in millimeters, which you can calculate from your device's screen size. For professional printing, ensure your target page size matches the print shop's specifications exactly and check whether bleed margins are required — if so, the target MediaBox should be larger than the final trim size. For presentation use (sharing on screen), sizing to 16:9 aspect ratio (e.g., 338 × 190 mm) makes the PDF fill a widescreen display cleanly, which is useful for slide-like documents exported as PDFs from tools that do not support proper 16:9 export.