A4 or Letter? Which size to send abroad

The short answer: match the country that will print it

Send the paper size of the country where the document will be printed. In India, the UK, most of Europe, Australia and most of the world, that is A4. In the USA and Canada, it is Letter. If nobody will print your file and it will only be read on a screen, the size hardly matters, and a PDF that is already A4 can travel to the USA exactly as it is.

• Printed in India, Europe, Australia and most other places: A4.
• Printed in the USA or Canada: Letter.
• Only read on a screen, or you can't tell: leave the file as it is, and ask if the instructions are unclear.

People worry about this when they send papers to a college, an employer, an embassy or a relative abroad. The worry is fair: the two sizes are close but not equal, and a printer can cut off the edge of a page that doesn't match its paper. The fix is small, though: Resize PDF can switch a finished PDF between the two in your browser, without uploading it.

A4 and Letter: how they really differ

Letter is about 6 mm wider than A4, and A4 is about 18 mm taller. Neither is simply "bigger": A4 has a little more paper in total, but Letter is broader. Lay one sheet over the other and A4 sticks out at the top and bottom, while Letter sticks out at the sides.

Why one can't fill the other

The shapes differ. Every A size has the same shape: cut an A3 sheet in half and you get two A4 sheets, cut an A4 in half and you get two A5. The long side of each is about 1.41 times its short side. For Letter it is only about 1.29 times.

So no amount of scaling makes an A4 page fill a Letter sheet exactly. Scale the page to the sheet's height and there is spare width, so white strips appear at the sides. Scale it to the width and the page runs off the top and bottom. A careful converter keeps the whole page and accepts the strips.

The A sizes follow a standard that started in Germany about a hundred years ago and later became the international one. Letter is an inch-based size from North America. Each country simply kept the paper its offices and printers were built around.

Legal (8.5 × 14 inches) is as wide as Letter but longer, and is used for some legal papers in the USA. A3 and A5 belong to the A4 family. The paper table in the Resize PDF guide lists all five sizes the tool offers.

Which countries use A4, and which use Letter

A4 is the everyday size in India, the UK, Australia, China, Japan, across Europe and in most other countries.

Letter is the everyday size in the USA and Canada, and a few other countries, mostly in the Americas, use it too. An office printer in the USA or Canada is normally loaded with Letter paper.

Offices and colleges that deal with other countries see both sizes often. Print windows usually have a setting that fits the page to the paper, and with it your A4 page simply comes out slightly smaller on Letter paper. Trouble starts only when it is printed at actual size, or by someone in a hurry who skips the preview.

Not sure what they use? Ask: "Should the PDF be A4 or Letter?" takes five seconds. If your instructions name a size, follow them. If they name none, it is unlikely to matter.

Does it matter if the file is only read on a screen?

Hardly. A PDF reader on a phone or computer shows a page of any size, usually fitted to the screen's width. A Letter page looks a little shorter than an A4 page, and that is all the reader notices. It matters in three cases:

• Someone will print it. A page bigger than the sheet loses its edge at actual size. An A4 page on Letter paper is about 18 mm too tall, so a strip at the top or bottom can be lost, sometimes with a line of text in it. A Letter page on A4 paper is about 6 mm too wide, so a few millimetres can go at the sides. With "fit to page" nothing is lost and the page just prints a bit smaller. The printing section of the guide explains both settings.
• The instructions name a size. Some portals and offices say "A4 pages only". When they say it, do it.
• Pages must match each other. A file that mixes sizes jumps from page to page on screen and prints with odd margins.

One thing never changes: the file's weight. Switching between A4 and Letter leaves the file about as big as it was, so it won't help or hurt an email attachment or a size limit. That is a separate job, covered further down.

What to send, situation by situation

A worked example

Say you are applying for a master's course in Canada. You have a resume and a statement of purpose in Word, and four scanned mark sheets. The first two are yours, so set Word's paper to Letter and save them as PDF again. The mark sheets came from your college on A4 paper, so leave them as A4 scans. The people reading your application will see them on a screen, and nobody minds a mark sheet that is a little narrower than the page next to it.

If you wrote the document, set the paper before you save

Word, Google Docs and LibreOffice all let you choose the paper size. In Word, look for the Size button on the Layout tab (Page Layout in older versions). In Google Docs, open Page setup from the File menu. Change it first, then save as PDF.

A computer set up for the USA often starts new documents on Letter, even in India, so a resume you typed long ago may already be Letter. Open the paper settings and look.

Switching in either direction can move lines onto a new page. A resume that was exactly one page on A4 may spill a few lines onto a second page on Letter, because Letter is about 18 mm shorter. Check the page count every time. With a PDF you received, or a scan, there is no writing app to go back to, so converting the PDF is the only way.

Starting from photos of papers? JPG to PDF lets you pick A4 or Letter pages while it builds the PDF, so the pages come out the right size from the start.

Switch a finished PDF between A4 and Letter

Resize PDF does this on a phone or a computer, and the PDF never leaves your device:

1. Open Resize PDF and choose Page size (A4) under "What to change". Despite its name, this option offers every paper size the tool has.
2. Pick the paper under "Paper size": Letter if the PDF is going to the USA or Canada, A4 if it is coming from there.
3. Leave Direction on "As it is". Upright pages stay upright and sideways pages stay sideways.
4. Choose your PDF. The result says something like "All pages now Letter (8.5 × 11 in)", or "3 of 10 pages now Letter" if some already were.
5. Download it. The new name ends in the paper you picked, like resume-Letter.pdf. Your original stays as it was.

If every page already has that size, the tool says "Every page is already Letter, so you can keep your original file." That makes it a quick way to check whether a PDF is already the size you need.

What the pages look like afterwards

• A4 to Letter: A4 is the taller page, so each page is scaled down to fit Letter's height and centred, with thin white margins at the left and right.
• Letter to A4: each page is scaled to about 97% to fit A4's width, leaving about 13 mm of white at the top and bottom.
• Nothing is cut off or stretched. Text stays text, so it stays sharp and searchable, and links, form fields, comments and bookmarks keep working.

In our tests, a 117-page A4 textbook became Letter in 3.9 seconds, and a 14-page Letter paper became A4 in 0.4 seconds. Times on your device may be shorter or longer.

The tool runs inside your browser, so transcripts, passport copies and certificates are not uploaded to any server.

When it is better not to convert at all

• The PDF is digitally signed. Changing the file ends the signature's validity, and the tool warns you when it sees one. Keep the signed original for anyone who must check it.
• The PDF is locked with a password. The tool can't open it, and tells you to remove the password first with Unlock PDF, which needs the password.
• It is a good A4 scan already. Moving it onto Letter makes everything on it a little smaller, small print too. If you do it, check roll numbers and dates.
• Its pages have dark or coloured backgrounds. White strips show clearly against colour, while a white page hides them.
• It is Legal size. A long Legal page has to shrink a lot to fit Letter or A4, with bands of white at the sides. Check the small print.
• The other side never asked. If the instructions don't name a size, a change you don't need only adds a chance for a mistake.

Most people sending papers abroad are better off with clear files that arrive on time than with files in exactly the right paper size.

Sending a whole bundle: the right order

When several papers go in one file, this order avoids doing anything twice:

1. Turn sideways scans upright with Rotate PDF. A scan with the page lying on its side is wider than it is tall, so "As it is" puts it on a sideways sheet, still lying on its side. Turn it upright first.
2. Join the parts in the order asked, with Merge PDF. It keeps each page's own size, so Letter and A4 pages can sit in one file for now.
3. Change the page size of the joined file, if you want every page the same.
4. Make it smaller last, if there is a limit. For a number, such as "under 2 MB", the guide's step-by-step shows the right order for page size and file size. With no number to meet, use the PDF compressor.
5. Look at the result. Scroll through every page, count them, check the order and zoom in on the small print.

For email, Gmail attachments can be up to 25 MB, and bigger files are sent as a Google Drive link. A bundle of scans can easily pass that, and changing between A4 and Letter will not bring it down.

What Resize PDF can't do for A4 and Letter

It moves finished pages onto new paper. That is the whole job, so a few things are out of its reach:

• It can't make the strips go away. A4 and Letter have different shapes, so pages are scaled to fit and never cropped. If you want text right up to the usual margins, set the paper in the app that made the document.
• It can't reflow your words. Line breaks and page breaks stay where they were. Only the writing app can rearrange text for the new paper.
• It offers five sizes, not every size. A4, Letter, Legal, A3 and A5. If someone asks for a size outside these, there is no custom size to type in.
• It gives every page the same paper. You can't keep some pages A4 and turn others into Letter in one go.
• It doesn't make the file smaller. A size in KB or MB is a separate choice on the same page.

For password-locked and signed files, and the other limits, see the limits section of the guide.

Quick answers about A4 and Letter

Is Letter bigger than A4?

Neither is bigger in every direction. Letter is about 6 mm wider, A4 is about 18 mm taller, and A4 has a little more paper in total.

Is A4 the same as 8.5 × 11?

No. A4 is 8.27 × 11.69 inches. The size 8.5 × 11 inches is Letter, also called US Letter.

Can I send an A4 PDF to the USA?

Yes. It opens on any computer or phone, and only printing needs care. If you know it will be printed and can send Letter, that is a helpful extra step.

Will a Letter PDF print on an A4 printer?

Yes, if the print window is set to fit the page. At actual size, a few millimetres at each side can be lost, so check the print preview.

Do I need Legal size?

Only if someone asks for it.

Is it safe for passport copies and certificates?

Yes. Your PDF is changed on your own device and never uploaded. Most online PDF tools do upload your file to their servers, so it is worth checking whenever you use one.