Journal / Paper guides / Paper Sizes: ISO vs ANSI, Letter, Legal, A4, and 11x17

Published January 26, 2026 · Updated May 31, 2026 · 8 min readSection / Journal

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Paper Sizes: ISO vs ANSI, Letter, Legal, A4, and 11x17

Compare ISO and North American paper sizes: A4, A3, Letter, Legal, Tabloid, Ledger, and 11x17. Choose the right size before exporting PDFs.

PGPaperGens · writing about print·January 26, 2026·Updated May 31, 2026·8 min read

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Paper sizes matter because the sheet is part of the document. A4, A3, Letter, Legal, Tabloid, Ledger, and 11x17 are not interchangeable labels. They change page shape, printable area, margins, line counts, grid spacing, file names, printer trays, and what users expect when they download a PDF.

For ordinary reading copies, a printer can often shrink or center a mismatched page. For printable templates, that is risky. A graph grid, ruled sheet, handwriting guide, staff paper, form, label, or cut line needs the page size to be correct before export.

Quick answer

User or printer context	Safer default
United States or Canada school and office printing	Letter
International classroom and office printing	A4
Long forms, legal pads, or extra vertical room	Legal
Posters, large tables, spreadsheets, or spreads	11x17, Tabloid, or Ledger
ISO poster and diagram workflows	A3 or A2
Mixed download audience	Publish separate A4 and Letter PDFs

Use the paper size that matches the printer tray and the reader's region. If exact spacing matters, do not rely on Fit to page.

ISO vs North American sizes

The ISO A-series is metric. A4, A3, A2, and related sizes share the same aspect ratio, so each size folds or cuts cleanly into the next. A3 is twice the area of A4. A2 is twice the area of A3.

North American office sizes are inch-based. Letter, Legal, Tabloid, and Ledger are common in the United States and Canada, but they do not follow the ISO A-series sequence.

System	Common sizes	Main use
ISO A-series	A4, A3, A2, A5	International documents, school sheets, posters, metric workflows
North American office	Letter, Legal, Tabloid, Ledger	US/Canada offices, classrooms, forms, large spreadsheets
Architectural / engineering	Arch sizes, ANSI drawing sizes	Plans, construction drawings, engineering plots

The most common mismatch is A4 vs Letter. A4 is narrower and taller. Letter is wider and shorter. That small difference can still clip a footer or shrink a measured printable.

Common paper size chart

Size	Dimensions	Best use
A4	210 x 297 mm, 8.27 x 11.69 in	International office documents, worksheets, A4 templates
A3	297 x 420 mm, 11.69 x 16.54 in	Posters, diagrams, two-up A4 proofs
A2	420 x 594 mm, 16.54 x 23.39 in	Larger posters, display boards, print-shop output
Letter	8.5 x 11 in, 215.9 x 279.4 mm	US documents, school handouts, binders
Legal	8.5 x 14 in, 215.9 x 355.6 mm	Legal forms, contracts, taller writing pages
Tabloid	11 x 17 in, 279.4 x 431.8 mm	Portrait 11x17 posters and newsletters
Ledger	17 x 11 in, 431.8 x 279.4 mm	Landscape 11x17 tables and wide forms

Use this table for routing and file naming. Use the detailed resource pages when you need exact intent coverage:

How to choose for printable templates

Start with the user action, not the standard name.

Choose Letter when the page will be printed in a US classroom, added to a US binder, copied on a US office device, or mixed with ordinary 8.5 x 11 in paperwork.

Choose A4 when the audience is outside North America, the workflow is metric-first, or the page will be printed on A4 office paper.

Choose Legal only when the extra height solves a real problem: longer forms, legal note pages, contracts, clipboards, or layouts that need more vertical space without getting wider.

Choose Tabloid or Ledger when the content needs a larger sheet: spreadsheets, posters, storyboards, large graphs, accounting layouts, or two-page proofs.

Choose A3 or A2 when the workflow is ISO poster or diagram output and the printer or print shop can handle large metric sheets.

Why standards affect SEO and site structure

Paper-size search intent is often exact. A user searching legal paper size wants the Legal dimensions and maybe a matching template. A user searching A4 size in inches wants a conversion and a warning about Letter. A user searching 11x17 paper may need the Tabloid/Ledger naming difference.

That means one generic article cannot own every query. The better structure is:

A paper-size hub for broad browsing.
Dedicated resource guides for exact dimensions.
Supporting blog posts for comparisons, printing workflows, and mistakes.
Template detail pages for printable downloads.

This article supports the broad standards question. It should point users toward the exact guide when they know the size they need.

Printing across regions

Cross-region printing is where standards cause the most frustration. A US-made Letter PDF sent to an A4 printer may shrink or reflow. An A4 worksheet sent to a Letter printer may clip at the bottom. A measured template can look fine in a browser preview and still print at the wrong size.

Use this checklist:

Set the source document to the destination page size.
Export a PDF with the correct page box.
Put the sheet size in the file name, such as worksheet-a4.pdf.
Select the matching printer media or tray.
Use Actual size or 100% for measured templates.
Print one proof and measure a known grid, line spacing, or border.

For a mixed audience, publish separate A4 and Letter downloads. One file plus "scale as needed" creates support issues and weakens trust in the template.

Printer dialog settings

The same page can pass through several settings before it reaches paper: source document setup, PDF export, PDF viewer, browser print dialog, operating-system printer dialog, and the printer driver. Any one of those layers can change the final size.

Watch for:

Fit to page: may shrink or enlarge the page.
Shrink oversized pages: can turn a large format into a smaller print.
Scale to printable area: changes measured grids and line spacing.
Auto rotate: can change Tabloid/Ledger orientation.
Wrong tray: sends the right PDF to the wrong paper.

For printable templates, prefer Actual size and matching media. If the printer cannot feed the correct paper, use a version designed for the paper it can feed.

Template recommendations

Use templates that already match the intended paper family:

Need	Recommended template
International A4 notes and handouts	A4 college ruled paper
US Letter notes and classroom pages	Letter college ruled paper
Legal-height writing and forms	Legal ruled paper

Common mistakes

Treating A4 and Letter as the same size.
Publishing only one download for a mixed global audience.
Designing measured templates in one size and resizing at print time.
Forgetting that Tabloid and Ledger are the same sheet in different orientation.
Using a slide canvas for a printable handout without setting page size.
Assuming a print shop's trim workflow preserves graph or ruling scale.
Naming files final.pdf instead of including the paper size.

The fix is simple: choose the paper size before layout, export the PDF in that size, and connect the article to the matching template or resource guide.

FAQ

Is A4 the same as Letter? No. A4 is 210 x 297 mm. Letter is 8.5 x 11 in. A4 is narrower and taller.

Is Tabloid the same as Ledger? They use the same 11 x 17 inch sheet. Tabloid usually refers to portrait orientation, while Ledger usually refers to landscape orientation.

Which size should I use for international downloads? Offer A4 and Letter separately when the audience includes both ISO-paper and North American users.

Can I use fit to page for printable templates? Avoid it when spacing matters. Fit to page changes line spacing, grid pitch, margins, and cut marks.

Where should exact dimension queries go? Route users to dedicated size guides such as A4, Letter, Legal, 11x17, A3, A2, Long Bond, or Arch E.

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