Page size affects how your content flows, where line breaks fall, and how much fits on each page. This reference guide covers the three standard sizes, their dimensions, and when to use each.
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Page size is not just about paper dimensions. It determines how web content reflows into your PDF: where headings break across pages, how tables fit within the content area, how much text appears on each page, and whether your document feels spacious or cramped. The difference between a well-chosen page size and a poorly chosen one is the difference between a document that reads naturally and one that fights its own layout on every page.
When you convert a web page to PDF, the rendering engine takes continuous, scrollable content and divides it into fixed-size rectangles. The dimensions of those rectangles control everything. A narrower page forces earlier line breaks in paragraphs and may cause wide tables or code blocks to wrap or overflow. A taller page means more content per page and fewer page breaks overall, but it also means each page takes longer to read. A shorter page gives you more frequent breaks, which can make dense technical content easier to navigate but may split sections awkwardly.
Choosing the right page size before you generate your PDF avoids these problems. It is a small decision that has an outsized impact on the final result, and most people never think about it because their tools make the choice for them. Understanding the three standard sizes and when each one works best puts you in control of how your document looks and reads.
A4 is the international standard paper size, defined by the ISO 216 specification and used in virtually every country outside the United States and Canada. It measures 210 millimeters wide by 297 millimeters tall, or approximately 8.27 by 11.69 inches. If you have ever handled a sheet of paper anywhere in Europe, Asia, Africa, South America, or Australia, you have used A4.
Compared to US Letter, A4 is slightly narrower (about 6 mm less) and noticeably taller (about 18 mm more). This taller, narrower aspect ratio gives A4 documents a distinctive vertical feel. Text lines are slightly shorter, which can actually improve readability for body text since the eye has less distance to travel from the end of one line to the beginning of the next.
A4 is the best choice for international documents, academic papers (most journals and conferences require A4), content shared with non-US recipients, and any situation where you are unsure of your audience's location. It is the default page size in Pretty PDF Printer for international users, and it is the safest default overall because most US printers can handle A4 paper without issues.
US Letter is the standard paper size in the United States and Canada. It measures 8.5 inches wide by 11 inches tall, or 215.9 by 279.4 millimeters. If you have ever used a standard sheet of printer paper in North America, you have used Letter size. It is the default paper loaded in virtually every office printer, home printer, and copy machine across the US.
Compared to A4, Letter is slightly wider (about 6 mm more) and noticeably shorter (about 18 mm less). The wider format gives tables and images a bit more horizontal space, which can be helpful for documents with wide data tables or side-by-side layouts. The shorter height means slightly less content per page compared to A4, which results in marginally more pages for the same document.
US Letter is the best choice for documents destined for US business contexts, content that will be printed on US printers, and documents shared primarily with US-based teams. If your audience is entirely within the United States, Letter avoids any minor scaling or margin adjustments that can occur when printing A4 content on Letter-sized paper.
US Legal shares the same 8.5-inch width as Letter but extends to 14 inches tall, adding a full 3 inches of vertical space. In metric terms, it measures 215.9 by 355.6 millimeters. This extra height makes Legal the tallest of the three standard sizes and gives it a distinctly elongated appearance.
The additional vertical space means significantly more content fits on each page. A document that runs to 10 pages on Letter might only need 8 pages on Legal. This makes Legal particularly well-suited for legal documents, contracts, agreements, and lengthy forms where minimizing page breaks improves readability and reduces the chance of important clauses being split across pages.
Legal is less common for general-purpose documents and most office printers do not keep Legal-sized paper loaded by default. However, it is standard in legal and governmental contexts throughout the United States. If you are generating PDFs of contracts, terms of service, regulatory filings, or any document where continuous reading flow matters more than standard page dimensions, Legal is the right choice.
All three standard page sizes at a glance, with dimensions, typical regions, and common use cases.
| Size Name | Width (mm) | Height (mm) | Width (in) | Height (in) | Region | Common Use |
|---|---|---|---|---|---|---|
| A4 | 210 | 297 | 8.27 | 11.69 | International | General documents, academic papers, international business |
| US Letter | 215.9 | 279.4 | 8.5 | 11 | US & Canada | Office documents, business reports, US printing |
| US Legal | 215.9 | 355.6 | 8.5 | 14 | US (legal) | Contracts, legal filings, lengthy forms |
When web content is converted to PDF, the page dimensions directly control how that content is laid out. The differences between A4, Letter, and Legal are not just abstract measurements. They produce visible, practical differences in the resulting document.
Line breaks and text flow. Narrower pages (A4) mean slightly earlier line breaks in every paragraph. A sentence that fits on one line in Letter format might wrap to two lines in A4. Over a long document, this adds up: the same content will produce slightly more pages in A4 than in Letter. The difference is usually small, around 2 to 5 percent more pages, but it is noticeable.
Tables. Wider pages (Letter) give tables more horizontal space. If you are converting a webpage with wide data tables, Letter may allow an extra column to fit without wrapping. A4's narrower width can cause table cells to wrap text more aggressively, which makes dense tables harder to read.
Code blocks. Code blocks are particularly sensitive to page width. Long lines of code that fit within the content area on Letter may wrap on A4's narrower page. This can affect readability for technical documentation, especially when precise line structure matters. Legal, with the same width as Letter, does not help with horizontal space but its extra height means fewer page breaks interrupting long code listings.
Images. Images in web-to-PDF conversion are typically scaled to fit the content area width. On narrower pages (A4), images will be rendered slightly smaller. On wider pages (Letter, Legal), they get a bit more room. The difference is subtle for most images but can matter for diagrams or screenshots where detail is important.
Page breaks. Taller pages (Legal, then A4, then Letter) mean fewer page breaks for the same content. Fewer page breaks generally means fewer awkward splits in the middle of sections, tables, or code blocks. If you find that your PDFs are breaking at inconvenient points, switching to a taller page size can help.
If you are unsure which page size to use, these guidelines will help you make the right choice quickly.
Sharing internationally? Use A4. It is the global standard and will look correct to recipients in any country. Most US printers handle A4 without issues, so even if some of your readers are in the US, A4 works.
US-only audience? Use Letter. It matches the paper that US recipients have in their printers, avoids any minor scaling, and is the expected format in American business contexts.
Legal or contractual documents? Use Legal. The extra height reduces page breaks in long documents, keeping clauses and sections together. It is the expected format in US legal contexts.
Not sure? Default to A4. It is the safest choice for several reasons. It works everywhere internationally. Most US printers can print it without issues. Its slightly narrower width actually improves readability for body text. And if you ever need to change, you can simply select a different size and regenerate your PDF.
In Pretty PDF Printer, you can set your preferred page size in the extension settings or save it as part of a print profile. This means you choose once and every PDF you generate uses your preferred size automatically, unless you override it for a specific document.
A4, Letter, or Legal. Choose your page size, pick a template, and get a professional PDF in seconds.
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