The standard sizes you'll encounter

Letter is 8.5 inches wide by 11 inches tall. It's the default paper size in the United States, Canada, and Mexico. When you open a word processor or hit print without changing settings, Letter is what comes out.

Legal is 8.5 inches wide by 14 inches tall — the same width as Letter but 3 inches longer. It's used for contracts, court documents, and formal agreements. Many printers can handle it, but you have to select it manually.

A4 is 210 millimeters wide by 297 millimeters (about 8.3 by 11.7 inches). It's the standard in Europe, Asia, Australia, and most of the world outside North America. If you're printing something from a European website or sending a document to someone abroad, it's probably A4.

There are smaller sizes too — A5 is half the size of A4, and is used for notecards and small flyers. Tabloid is 11 by 17 inches and is used for posters and large documents. But Letter, Legal, and A4 are the three you'll actually encounter in everyday use.

Key Takeaways

  • Letter (8.5 by 11 inches) is the default in North America; Legal (8.5 by 14 inches) is longer and used for formal documents.
  • A4 (210 by 297 millimeters) is the standard outside North America and is slightly narrower and taller than Letter.
  • Your printer can usually handle all three, but you have to tell your computer which size you want before printing.
  • Choosing the wrong size won't damage your printer — it just means your document won't fit the page the way you intended.

Why the sizes are different

Letter and Legal exist because the United States set its own standard decades ago, before international coordination happened. The 8.5-inch width was chosen because it fit the machinery of the time. Legal straightforward added length for documents that needed more room.

A4 and the other A-series sizes come from an international standard called ISO 216, adopted in the 1970s. The A-series is based on a mathematical ratio — each size is exactly half the previous one when you fold it in half. This makes them efficient for copying and scaling documents. Most of the world uses this system because it's more logical, but North America never switched.

How to check what size your printer uses

Open the settings for whatever program you're printing from — Word, Google Docs, a web browser, or anything else. Look for a "Print" or "Page Setup" option. You'll see a dropdown menu that says "Paper Size" or "Page Size." The current selection is what will print.

If you're not sure what your physical printer can handle, check the paper tray. Most printers have a label or guide showing which sizes fit. If you're still uncertain, the printer's manual (usually available online by searching the model number) will list every size it supports.

Changing the setting is straightforward: just click the dropdown and select a different size. The next time you print, that size will be used instead. You can change it back just as easily.

What happens if you print the wrong size

If you select A4 but only have Letter paper in the tray, your printer will either print anyway and cut off the bottom of the page, or it will pause and ask you to load A4 paper. Most modern printers are smart enough to warn you rather than waste paper.

If you select Letter but your document was designed for A4, the text or images might not fit the way the designer intended. Margins might be wrong, or a page break might land in the middle of a sentence. The document still prints — nothing breaks — but it looks off.

The safest approach is to match your paper size setting to the paper actually in your printer. If you're printing something from another country, check what size it was designed for before you print.

International paper sizes beyond A4

The A-series goes from A0 (huge, used for posters) down to A10 (tiny, smaller than a postage stamp). In practice, you'll only see A4, A5, and occasionally A3 (which is two A4 pages side by side).

There's also a B-series and C-series, used for envelopes and specialized printing. B5 is sometimes used for notebooks. C4 and C5 are standard envelope sizes in Europe. But unless you're ordering custom envelopes or working in graphic design, you won't need to know these.

Some countries use their own sizes too. Japan uses a system called JIS that's similar to ISO but slightly different. If you're printing something from a Japanese source and it looks wrong, this might be why.

Choosing the right size for your document

If you're in North America and printing for yourself or for a North American audience, use Letter. It's what everyone expects, and it's what your printer defaults to.

If you're printing a formal contract, legal document, or something that needs extra length, use Legal. Courts and law offices expect it.

If you're sending a document to someone outside North America, or if the document came from a European or international source, use A4. It's the global standard.

If you're designing something yourself and don't know what to choose, Letter is the safe default. It's what most people have paper for, and it's what most printers are stocked with.

Frequently Asked Questions

Can I print A4 on a Letter-sized printer?

Yes. A4 is slightly smaller than Letter (about 0.2 inches narrower and 0.7 inches taller), so it will physically fit in most printers. The content will print, but the margins might look uneven because A4 and Letter have different proportions.

Do I need a special printer for A4?

No. Nearly every printer sold in the last 20 years can handle both Letter and A4. You just change the setting in your software before printing. The only exception is very old or very specialized printers.

What size is standard for resumes?

In North America, Letter. Everywhere else, A4. If you're sending your resume to an international company or explore for a job outside North America, use A4 instead.

Why does my document look different when I print it?

The most common reason is a mismatch between the page size your document was designed for and the page size you're printing to. Check that your software's page size setting matches the paper in your printer.

Can I print Legal size on regular paper?

Yes, if your printer supports it. Legal paper is just taller Letter paper — it's the same width. Load Legal-sized sheets into your printer, set the page size to Legal in your software, and print normally.