Resize PDF to the size you need

Two kinds of resizing

When people say "resize a PDF", they mean one of two things, and this tool does both:

• File size: how much space the file takes, in KB or MB. Upload forms care about this, as in "PDF under 100 KB". This is what most people need.
• Page size: the size of the paper, like A4 or Letter. Printers and some offices care about this.

The two are separate. Making a PDF smaller in KB keeps every page the same size on paper, and changing the paper size keeps the file about as big as it was. Choose File size or Page size at the top of this page.

Resize or compress: which one do you need?

PDFGuild has two tools that make PDFs smaller. Here you choose the size. In the tool that lets you compress a PDF with no size target, you choose the quality.

If a website gives you a number, such as "under 200 KB", use Resize: it lands just under that number. A level can't aim at a number. Even Smallest keeps pictures at up to 100 ppi, while our test scans went down to 48 to 73 ppi to fit under 100 KB.

With no number to meet, use the compressor for email or storage. Its Recommended level keeps pictures at up to 150 ppi, where our results start to say Sharp.

Why forms ask for 100 KB or 200 KB

Job, exam, admission, scholarship, bank and government websites often accept a PDF only under a set size, such as 50 KB, 100 KB, 200 KB, 500 KB or 2 MB. The limit keeps their servers fast when thousands of people apply at once.

Scans are much bigger than that. Our sample file, a 4-page scan at 300 pixels per inch like an office scanner makes, is 9.96 MB: about 2.5 MB a page. Photos from a phone camera are often several MB each. A file even slightly over the limit is usually refused, sometimes after you have filled in the whole form.

PDFGuild makes the file fit and keeps it as clear as the limit allows, so the person on the other side can still read every word. For the two most common limits there are pages with the size already picked, and guides on how many pages stay readable: compress a PDF to 100 KB and compress a PDF to 200 KB.

Step by step: a scan for an exam, job or visa form

Say a form wants your marksheet as a PDF under 100 KB. Here is the whole way, from paper to upload:

1. Scan or photograph it. On a scanner, choose 150 to 300 dpi, and grayscale for black-and-white papers. On a phone, use a scanner app, which straightens and crops the page. Lay the page flat, in good light.
2. Put the pages in one PDF, in the order the form expects. Scanner apps can usually save several pages as one file. If you only have photos, turn photos of your documents into a PDF. If the form wants separate files, make one PDF for each.
3. Pick the form's limit under File size, or pick Other and type it. Don't pick less to be safe: we count 1 KB as 1,000 bytes, which fits every website's limit.
4. Add your PDF and check the result. Open the new file and zoom in on the small print, such as roll numbers, dates and stamps. If it is hard to read, see When your PDF still won't fit.
5. Upload it. Its name ends in the size you picked, like marksheet-100KB.pdf. Keep your original scan for forms with other limits.

If the form also asks for A4 pages, do the page size first, so that the size limit is checked on the file you upload:

1. Choose Page size, pick A4, add your PDF and download the A4 copy. If your pages are already A4, the resizer says so, and you can skip this step.
2. Choose File size, pick the limit and add the A4 copy. Upload the file whose name ends in A4 and your size, like marksheet-A4-100KB.pdf.

How the size finder works

Hitting an exact size is harder than it sounds, because nobody can tell in advance how small a PDF will get. So the resizer tries, measures and adjusts:

1. First try. It makes the file with our Recommended setting, which keeps pictures at 150 pixels per inch.
2. Find the edges. If that is still too big, it tries the strongest setting to see how small the file can get. If it already fits, it tries the gentlest setting to see whether full quality fits too.
3. Close in. Each next try aims between the closest result that fits and the closest that doesn't, until one lands just under your size, within 15% of it.
4. Keep the best. You get the sharpest version that fits, after six tries at most.

Only pictures change. Text, fonts, lines and drawings are copied as they are, so words stay sharp and searchable at any size. For pictures, each step lowers the sharpness (from 220 down to 30 pixels per inch) and the JPEG quality (from 85 down to 15) a little at a time.

We count 1 KB as 1,000 bytes, so a file under 100 KB here is also under 100 KB on websites that count 1 KB as 1,024 bytes.

Real results

We resized these files in Chromium, the open-source browser Google Chrome is built on, on our test computer. "Your size" is the limit we picked, and "After" is the file the resizer made. Times on your device may be shorter or longer.

• 91 KBfrom a 9.96 MB scan, for a 100 KB limit
• 2 to 5tries to land just under your size
• 1 to 5 sfor scans up to 10 MB
• 0 bytesof your PDF sent to any server

Scans fit even small limits, because they are made of pictures. Text-heavy PDFs are different: the 14-page paper fit under 1 MB at full picture quality, but the 117-page textbook can't go below 2.56 MB, because most of it is text and drawings, which we keep sharp. When that happens, the result says so, and you still get the smallest version.

It is light on your device, too. Resizing the 6.37 MB scan needed 65 MB of memory and one processor core for four seconds, and the memory was handed back as soon as the file was done.

How sharp it stays

Every result tells you in one word how sharp the pictures stayed. The word comes from the pixels per inch (ppi) the pictures kept:

In our tests, normal-sized text in a scan could still be read at 48 ppi, though it looked soft, and read easily at 57 ppi. If you see Rough and the website allows a bigger file, pick a bigger size and press the Redo button on the file's row, such as Redo at 200 KB.

When your PDF still won't fit

Sometimes the result says Over instead of Under your size, because the file can't get any smaller. Or the file fits, but says Rough and the small print is hard to read. Either way, try these:

1. Send only the pages they ask for. All the pages share one limit, so each page you leave out gives the rest more room. This works for every PDF, text-heavy ones too. To take the pages out, split the PDF into smaller files and keep the ones you need.
2. Scan again in grayscale. A grayscale scan has no colour to store, so more of the limit goes to sharpness. Keep colour only for papers where it matters.
3. Scan again at a lower setting. 150 to 300 dpi is plenty for text: a higher setting only makes the file bigger and slower to resize. Lay the page flat in good light, too, as shadows and grain take up room the words could use.
4. Start from the original. A copy that was already made smaller has lost detail for good. If you made a 100 KB copy for one form, go back to your first scan for the next.

Why text-heavy PDFs have a smallest size. Only pictures get smaller. Text, fonts and drawings are copied as they are, so words stay sharp and searchable. Once the pictures are as small as they go, the rest can't shrink without losing words: that is why our 117-page maths textbook stopped at 2.56 MB.

For a PDF like that, fewer pages is what helps. Our compressor keeps text the same way, so it can't go lower either.

Change PDF page size to A4 or Letter

Choose Page size to give every page the same paper size. Each page is scaled to fill the new paper as far as its shape allows and centred on it, so nothing is cut off. When the shapes differ, for example Letter to A4, a thin white margin appears on two sides.

• Links, form fields, comments and bookmarks move with the page and keep working.
• Text stays text. It is scaled, not turned into a picture, so it stays sharp and searchable.
• Pictures stay as they are, so the file stays about the same size.
• Direction: "As it is" keeps each page upright or sideways as it was; Portrait or Landscape puts every page on an upright or a sideways sheet, and scales what is on it to fit, without turning it.

In our tests, a 14-page Letter paper became A4 in 0.4 seconds, and a 117-page A4 textbook became Letter in 3.9 seconds. Pages that already have the size you pick are left as they are.

Printing after a page-size change

Print windows usually offer two ways to size the page, with names that differ from app to app:

• Actual size (or 100%) prints the page as big as it is in the PDF. Pick it when the PDF matches the paper, like an A4 PDF on A4 paper.
• Fit to page (or Fit to printable area) scales the page to suit the paper. Pick it when the sizes differ, or when the printer cuts off the edges, as many printers can't print right to the edge.

Changing the page size here first means the PDF already matches the paper, so it prints well either way. Check the print preview before you print many copies.

Why white margins appear. When the old and new paper have different shapes, the page can't fill the sheet exactly. Stretching would distort the text and cutting would lose part of the page, so we scale it to fit and centre it. Letter is a little wider and shorter than A4, so a Letter page is scaled to about 97% to fit A4's width, leaving about 13 mm of white at the top and bottom.

A4 to Letter works the other way round, with the margins at the left and right. A4, A3 and A5 share one shape, so between them a page just gets bigger or smaller and fills the sheet.

Tips for a small PDF

1. Scan in grayscale. Forms, marksheets and letters rarely need colour, and with no colour to store, more of the size limit goes to sharpness.
2. Send only the pages asked for. Every page shares the same limit, so fewer pages leave more room for each one.
3. Scan at 150 to 300 dpi. Higher settings make huge files without making text easier to read.
4. Start from the original. A file that was already squeezed has lost detail you can't get back.
5. Check before you upload. Open the new file and zoom in on the small print. If it isn't clear enough and the website allows more, pick a bigger size.

Resize PDFs on Android, iPhone, Windows and Mac

The resizer runs in your web browser, so there is nothing to install: no app, no extension and no account. It works the same way on phones, tablets and computers.

• Android

  Open this page in Chrome, Samsung Internet or another up-to-date browser. Tap "Choose PDF files", pick your PDF and choose a size. The new file is saved to your Downloads folder, ready to upload.

• iPhone and iPad

  Open this page in Safari or Chrome, tap "Choose PDF files" and pick a PDF from the Files app. The new file usually goes to Downloads in the Files app.

• Windows, Mac, Linux, Chromebook

  Use Chrome, Edge, Firefox or Safari, and drop one or many PDFs onto the page. The new files go to your Downloads folder.

You can add several PDFs at once. They are resized one after another, each gets its own Download button, and if you pick another size, files that are already finished keep their download and each offers a Redo button at the new size (Apply to all, for several files).

KB, MB, ppi and paper terms, explained

KB (kilobyte)

A measure of file size. We count 1 KB as 1,000 bytes, so "under 100 KB" means 100,000 bytes or less, which fits every website's limit.

MB (megabyte)

1,000 KB. A 2 MB limit is twenty times bigger than a 100 KB one, so pictures can stay much sharper.

PPI (pixels per inch)

How many picture dots fill one inch of the page. More pixels per inch means a sharper picture and a bigger file.

DPI (dots per inch)

The resolution setting on a scanner or printer. A page scanned at 300 dpi becomes a 300 ppi picture inside the PDF.

Portrait and landscape

A portrait page stands upright, taller than it is wide. A landscape page lies sideways, wider than it is tall.

Scale to fit

Making a page bigger or smaller without changing its shape, so that all of it fits on the new paper. Nothing is cut off.

Private by design

Forms ask for your most private papers: Aadhaar and PAN cards, marksheets, certificates and bank statements. With PDFGuild they never leave your device. The resizer runs inside your browser, the tool never sends your file anywhere, and it keeps working with the internet switched off once the page has loaded.

You can check this yourself in your browser's network panel: your file is never uploaded. Our guide to private compression explains how the protection works.

Limits

• PDFs that need a password to open can't be resized as they are. Remove the password from the PDF first with Unlock PDF, which needs the password.
• A PDF with a digital signature loses the signature's validity when it is changed.
• Text, fonts and drawings set a smallest size, so a long text document may not fit a very small limit.
• A small limit for a scan with many pages leaves little room for each page, so pictures get rough.
• Big files take longer, because each try is a full pass over the file: our 47.8 MB scan took 37 seconds to fit under 2 MB.
• Changing the page size doesn't make a file smaller. To do both, change the page size first, then make the new file smaller.