A4 vs Letter: Sizes, Differences and How to Print Between Them

The main difference in A4 vs Letter is shape: A4 measures 210 x 297 mm (8.27 x 11.69 inches) and is narrower and taller, while US Letter measures 8.5 x 11 inches (215.9 x 279.4 mm) and is wider and shorter. A4 is the standard in most of the world, and Letter is the standard in the United States and Canada. The two are close enough to be confused, and different enough to cut off the edge of a page when you print.

A4 vs Letter size: exact dimensions

In practice that means:

• Letter is wider by 5.9 mm (about 0.23 inch).
• A4 is taller by 17.6 mm (about 0.69 inch), roughly two extra lines of normal text per page.
• A4 has about 3% more area, so the same document can end up one page shorter on A4.

PDF files store page sizes in points, which is why you may see 595 x 842 or 612 x 792 in the document properties of a PDF reader.

Where A4 and Letter are used

A4 belongs to the A series defined in ISO 216. It is the everyday office and school paper in Europe, Asia, Africa, Australia and most of South America.

Letter is the everyday paper in the United States and Canada. It is also common in Mexico, the Philippines and parts of Latin America, so check before you assume.

The A series follows a neat rule. A0 is one square meter, and every next size is half of the one before: two A4 sheets side by side make A3, and an A4 folded in half is A5.

All A sizes share the same shape, so an A3 poster shrinks to A4 without white bands. Letter has no such family; its larger relatives, Legal (8.5 x 14 in) and Tabloid (11 x 17 in), have other shapes.

What happens when you print one on the other

Most printing problems come from the height. Here is what to expect with a normal printer, before any scaling.

The shrink is small enough that most readers never notice it. The real exception is anything that must print at an exact size, such as a sewing pattern, a scale drawing or a form with boxes for a scanner. For those, print at actual size on the right paper.

Some printers also stop with a paper mismatch message, because the file asks for one size and the tray holds another. Scaling to the loaded paper, as shown below, usually clears it.

How to print A4 on Letter paper (and back)

Windows 11 with Microsoft Edge

1. Open the PDF in Edge and press Ctrl and P.
2. Choose your printer, then open More settings.
3. Set Paper size to the paper in your tray, Letter or A4.
4. Under Scale, choose Fit to printable area (Actual size prints at 100%).
5. Click Print.

Mac

1. Choose File > Print and pick the paper in your tray from the Paper Size menu.
2. Scroll down and click Paper Handling.
3. Turn on Scale to Fit Paper Size and choose your paper under Destination Paper Size. Scale Down Only shrinks a page that is too big without enlarging smaller ones.
4. Click Print.

In Preview you will also see Scale to Fit with Print Entire Image, which keeps the whole page, and Fill Entire Paper, which may cut the edges.

Microsoft Word on Windows

Word for Windows has a print option that scales content for A4 or 8.5 x 11 paper sizes. You find it under File > Options > Advanced, in the Print section, and it is normally on. It lets an A4 document print on Letter paper, or the reverse, without changing the document itself.

How to set your default paper size

New documents use a default size, usually taken from your region. Here is how to change it.

Microsoft Word

1. On the Layout tab, click Size, then More Paper Sizes.
2. On the Paper tab, choose A4 or Letter under Paper Size.
3. Click Set As Default, confirm with Yes, then click OK.

Existing documents keep their size. To change one, use Layout > Size inside that document and check the page breaks afterward.

Google Docs

Click File > Page setup, make sure Pages is selected at the top, choose the Paper size, click Set as default and then OK.

Windows 11 printer

Go to Start > Settings > Bluetooth & devices > Printers & scanners, select your printer and choose Printing preferences. The paper size setting is often on a Paper or Layout tab, but names vary by printer maker.

Mac

Choose Apple menu > System Settings, click Printers & Scanners in the sidebar and pick a size from the Default paper size menu.

Convert a PDF between A4 and Letter

Printer scaling only changes one printout. If a school, employer or upload portal asks for a PDF in A4 or Letter, change the page size of the file itself.

1. Open Resize PDF and add one or more PDFs.
2. Choose A4 or US Letter. Legal, A3, A5 and Tabloid are also available.
3. Leave orientation on Auto, so portrait pages stay portrait and landscape pages stay landscape.
4. Pick a margin (None, Small or Large) and download. The size name is added to the file name.

Content is scaled to fit and centered without stretching, and text stays sharp vector text. Clickable links and fillable form fields are not carried over, so resize forms after filling them in and flattening them.

Other FileKiwi tools let you choose the paper while you create the PDF. JPG to PDF offers Fit to image, A4 or US Letter, and Excel to PDF and TXT to PDF offer A4 or US Letter. Word to PDF always creates A4 portrait pages, so a US reader may want a Letter copy made with Resize PDF afterward.

Design one document that works on both papers

If your file will be printed in several countries, you can avoid the problem instead of fixing it. The area that A4 and Letter share is 210 x 279.4 mm: the width of A4 and the height of Letter.

• Keep content inside the shared area. Margins of about 20 mm on every side keep text away from both the bottom edge of Letter and the side edges of A4.
• Watch the footer. Page numbers and legal small print sit at the bottom, which is exactly what gets lost when A4 prints on Letter. Give them extra room.
• Avoid full bleed backgrounds. Color that runs to the edge of an A4 page shows white strips on Letter, and the other way around.
• Do not rely on page breaks. A4 holds about two more lines per page, so a table that ends neatly on Letter can spill onto a new page on A4. Repeat table headers instead.

Pick the paper size that most of your readers use and check a printout or a PDF preview on the other size before you share the file widely.

Which paper size to use

• Sending to the US or Canada: Letter, unless the recipient asks for A4.
• Sending anywhere else: A4.
• International audience: choose the size most readers use and keep the content inside the shared 210 x 279.4 mm area.
• Exact size printing: match the paper to the document and print at actual size.

When in doubt, ask which paper the printer at the other end uses. One line in an email saves a reprint.

FAQ