PDF Page Sizes Explained: A4, Letter, Legal and More

Page size is one of those things nobody thinks about until something goes wrong — a document prints with cut-off margins, a form doesn't fit the page, or you receive a PDF that looks oddly proportioned. Understanding PDF page sizes prevents these headaches and helps you create documents that look professional everywhere they're viewed.

The Two Main Standards: ISO and North American

Most of the world uses the ISO 216 standard, which gives us the familiar A-series sizes (A0, A1, A2, A3, A4, A5...). The United States, Canada, and Mexico primarily use a separate system with sizes like Letter, Legal, and Tabloid. This split is the root cause of most page size confusion in international document sharing.

A4 — The Global Standard

Dimensions: 210 × 297 mm (8.27 × 11.69 inches)

A4 is the default paper size in virtually every country outside North America. It's slightly taller and narrower than US Letter. When you create a PDF in Europe, Australia, Asia, or Africa, it's almost certainly A4. Microsoft Word, LibreOffice, and most office software outside the US default to A4.

The A-series follows a clever mathematical relationship: each size is half the area of the previous size, with the same aspect ratio (1:√2 ≈ 1:1.414). A5 is half an A4, A3 is two A4 pages side by side.

US Letter — North American Standard

Dimensions: 215.9 × 279.4 mm (8.5 × 11 inches)

Letter is the standard US business and personal document size. It's slightly wider and shorter than A4. When you open Word on a US-configured Windows machine, Letter is the default. Most US office printers are loaded with Letter-size paper.

The difference between A4 and Letter looks small — 6mm wider, 18mm shorter — but it's enough to cause margin clipping when printing an A4 document on a Letter printer (or vice versa).

Legal — Longer US Format

Dimensions: 215.9 × 355.6 mm (8.5 × 14 inches)

Legal is the same width as Letter but 3 inches taller. It's used for legal documents, contracts, and some government forms in the US that need more vertical space. Less common than Letter for everyday use, but standard in US law firms and courts.

A3 — Large Format

Dimensions: 297 × 420 mm (11.69 × 16.54 inches)

A3 is twice the area of A4 and the international equivalent of Tabloid/Ledger. Used for posters, spreadsheets, engineering drawings, and any content that needs more space than a standard page. When you fold an A3 sheet in half, you get A4.

Tabloid / Ledger

Dimensions: 431.8 × 279.4 mm (17 × 11 inches) — Tabloid (landscape) / 279.4 × 431.8 mm (11 × 17 inches) — Ledger (portrait)

These are the same size, just in different orientations. Tabloid is used by newspapers; Ledger is used for large spreadsheets and architectural drawings in the US.

A5 — Half of A4

Dimensions: 148 × 210 mm (5.83 × 8.27 inches)

A5 is used for notebooks, small booklets, flyers, and compact documents. Exactly half an A4 sheet.

Executive and Statement (US)

Executive: 184.2 × 266.7 mm (7.25 × 10.5 inches) — used for executive correspondence and some sticky note pads.

Statement (Half Letter): 139.7 × 215.9 mm (5.5 × 8.5 inches) — half of a Letter sheet, used for small booklets and personal stationery.

How to Check a PDF's Page Size

In Adobe Acrobat Reader: Go to File > Properties > Description tab. Page size is listed there.

In Chrome or Edge: Open the PDF, press Ctrl+P (print), and the page dimensions appear in the print preview.

On Mac Preview: Go to Tools > Show Inspector > click the "i" tab.

How to Change PDF Page Size

If you receive an A4 PDF but need it in Letter size (or vice versa):

Print to PDF method: Open the PDF, go to print, and in the printer settings choose "Fit to page" or "Scale to paper size." Select your target paper size before saving as PDF.

Adobe Acrobat Pro: Go to File > Print Production > Crop Pages. Here you can set exact page dimensions.

Online tools: Services like PeacefulPDF can resize PDF pages to any standard size without quality loss.

Choosing the Right Size for Your PDF

Use A4 when your audience is primarily outside North America, or when you want maximum international compatibility.

Use Letter for documents primarily read or printed in the US or Canada.

Use Legal for US legal, real estate, or government documents where extra length is standard.

Use A3/Tabloid for presentations, infographics, or spreadsheets that need more space than a standard page.

When creating PDFs for digital-only distribution (no printing), size matters less — focus on aspect ratio and readability on screen instead.