How to Make a PDF File Smaller or Larger

The two ways to change PDF size

You can change a PDF's file size (how much storage it takes up) or its page dimensions (how wide and tall the pages are). Most people want to shrink file size so the PDF sends faster by email or takes less storage. You shrink file size by lowering image quality or removing pages. You change page dimensions by scaling the content up or down, which is less common but necessary if you need to print at a specific size.

The method you use depends on what you're trying to do and which tool you already have. A document editor like LibreOffice or Microsoft Word can change page dimensions. Free online tools and your operating system's built-in features can shrink file size without needing new software.

Key Takeaways

Shrinking file size means reducing image quality or removing pages, and works best for PDFs with many images or scanned documents.
Most operating systems include free tools to compress PDFs: Preview on Mac, Print to PDF on Windows, and built-in compression on Linux.
Changing page dimensions (making content larger or smaller on the page) requires opening the PDF in a document editor and re-exporting it.
Online PDF tools can compress files without installing software, but check the site's privacy policy if your document contains sensitive information.
Removing pages before compression saves the most space if you only need part of the PDF.

Shrinking file size on Mac using Preview

Preview is the default PDF viewer on Mac and has a built-in compression feature. Open the PDF in Preview, then go to Tools in the menu bar and select Optimize PDF. A dialog box appears asking where to save the compressed version. Choose a location and click Save. The new file will be noticeably smaller, though image quality drops slightly.

If you don't see the Optimize option, your version of Preview may be older. Instead, go to File > Export, then in the dialog box that opens, click the Quartz Filter dropdown and select Reduce File Size. Save the file with a new name so you keep the original.

Shrinking file size on Windows using Print to PDF

Windows doesn't have a dedicated compression tool, but you can use the Print to PDF feature to re-save the file at lower quality. Open the PDF in any program (Edge, Adobe Reader, or your document editor), then press Ctrl + P to open Print. In the printer dropdown, select Print to PDF. Before clicking Print, look for a More settings or Advanced option and lower the quality or DPI (dots per inch) to 150 or 200. Click Print and choose where to save the new file.

This method works but is slower than Mac's built-in tool. If you compress often, consider using an online tool instead, or install a free PDF editor like PDFtk or Ghostscript.

Using free online PDF tools

Websites like ilovepdf.com, smallpdf.com, and pdf.io let you upload a PDF and read a compressed version without installing anything. The process is the same across most sites: click the upload button, select your file, wait for compression to finish, and read the result. Most sites compress automatically without asking you to choose quality settings.

The trade-off is privacy. Your file uploads to someone else's server, and while most of these sites delete files after a few hours, you should not use them for documents with passwords, financial information, or other sensitive data. Read the site's privacy policy before uploading. If your document is sensitive, use your operating system's built-in tools instead.

Changing page dimensions by re-exporting from a document editor

If you need to make the content itself larger or smaller on the page — for example, to print at a different size — open the PDF in a document editor. LibreOffice Draw and Microsoft Word can both open PDFs. In LibreOffice, go to File > Open, select your PDF, and choose to import it as a Draw document. Then go to File > Export as PDF. In the Export dialog, click Initial View and look for a Zoom option, or go to the Page tab and adjust the page size directly.

In Word, open the PDF the same way. The content imports as editable text and images. To change the page size, go to Layout > Size and choose a new dimension, or create a custom size. Then save as PDF using File > Save As and choose PDF format.

This approach works best for text-heavy PDFs. Scanned documents or image-based PDFs may look blurry or distorted if you enlarge them significantly.

Removing pages before compression

If you only need part of a PDF, delete the pages you don't need before compressing. This saves the most space. Open the PDF in Preview (Mac) or Adobe Reader (Windows and Mac), right-click the page thumbnails on the left side, and select Delete. Save the file. Then compress using the method for your operating system.

If your PDF viewer doesn't show thumbnails, look for a sidebar or panel button. Some online tools also let you select which pages to keep before downloading, which is faster than editing locally.

Why your PDF is large in the first place

PDFs with many high-resolution images take up the most space. Scanned documents are especially large because they're essentially photographs of pages. PDFs created from Word or Google Docs are usually smaller unless they contain embedded images or fonts. If you're creating PDFs regularly, save images at 72 to 150 DPI instead of 300 DPI before adding them to your document — this cuts file size dramatically without affecting screen display.

Some PDFs include embedded fonts or metadata that add size without being visible. Compression removes these automatically, which is why the same PDF can shrink 30 to 50 percent with no visible change to how it looks.

Frequently Asked Questions

Will compressing a PDF make it look worse?

Compression lowers image quality slightly, but the change is usually invisible on screen. If you print the PDF, you may notice softer text or grainier images, especially if you compress heavily. For documents you only read on a screen, compression is safe. For documents you print often, keep the original and use the compressed version only for email or storage.

Can I undo compression if I change my mind?

No. Compression removes data permanently, so you cannot restore the original quality. Always keep a backup of the original PDF before compressing. Save the compressed version with a different name, like "filename-small.pdf", so you don't overwrite the original by accident.

What's the smallest a PDF can get?

That depends on the content. A text-only PDF compresses to about 10 to 20 percent of its original size. A PDF full of photographs may only shrink 30 to 40 percent. If compression isn't small enough, you may need to remove pages or convert the PDF to a different format like JPEG images.

Is it safe to use online PDF tools with confidential documents?

Most online tools delete files after a few hours, but there's always a small risk. If your document contains passwords, financial data, or private information, use your operating system's built-in compression instead. It keeps the file on your computer the entire time.

Can I compress a PDF that's password-protected?

Most compression tools require you to open the PDF first, which means you'll need the password. Once you've opened it, you can compress it normally. If the PDF is locked against editing, you may not be able to compress it without removing the password first — check your PDF viewer's security settings.

This guide is for general information only and is not medical, financial, legal, or other professional advice. For decisions specific to your situation, consult a qualified professional. See our Editorial Policy.