Find out what is making the PDF big
Right-click the file in File Explorer and choose Properties to see its exact size, then open it and look at what is inside. A PDF made of scanned pages or photos is large because each page is an image, and those compress dramatically. A PDF of plain text exported from Word is large only if it has many pages or embedded images, and will shrink much less.
Check the page count too. A 300-page manual at 12 MB is not unusually large for its length; the fix there is to send less of it, not to compress harder. A 3-page letter at 12 MB almost certainly contains an enormous image — a logo exported at poster resolution, or a full-resolution photo — and compresses easily.
Finally, find the limit you are aiming for. An email provider, an upload portal or a colleague’s mailbox may each allow a different maximum. The target is the lowest limit along the way, with some headroom to spare.
Why Print to PDF is not the answer
Windows includes a virtual printer called Microsoft Print to PDF, and a common suggestion is to open the PDF and “print” it to a new PDF. That produces a new file, but not reliably a smaller one. Depending on the content, the result can be smaller, about the same, or noticeably larger, and there is no setting to control the outcome.
It also strips things you might need. Re-printing tends to lose clickable links, bookmarks and fillable form fields, because printing captures how the page looks rather than how the document works. For a contract with a table of contents, or a form someone still has to complete, that is a real loss for an uncertain saving.
The same caution applies to opening a PDF in Word and saving it back. Word converts the PDF into an editable document and then exports a fresh one, which can shift layouts, substitute fonts and break tables. Use a tool designed to compress a PDF, rather than a chain of conversions that happen to produce one.
Compress the PDF in your browser
Open Compress PDF in Edge, Chrome or Firefox, drag the PDF from File Explorer onto the page, choose a level and download the smaller copy. There is nothing to install, no account to create and no watermark on the result. Your original file is left untouched.
The compression runs inside your browser on your own computer. The document is never uploaded, which matters on a work machine where company policy may prohibit sending files to unknown online services, and for any personal document you would not want copied to someone else’s server.
The compressor rebuilds each page as an image at the chosen quality. That is why it is so effective on scans, and it is also the trade-off to keep in mind: text in the compressed file is visible but no longer selectable. For a scanned document this costs nothing, because the text was never selectable in the first place.
Choose a level for the content
Start with Recommended. It suits most scanned and mixed documents and keeps ordinary text comfortably readable. Use Light when the file is only slightly over the limit, or when it has small print, fine lines or a detailed drawing that you want to keep crisp.
Use Strong only when a large scan has to meet a strict limit. It produces the smallest file but can soften fine detail, faint handwriting and light-coloured text. If you go to Strong, inspect the result closely — the guide to blurry compressed PDFs covers what to do if it went too far.
Always compress from the original. If Recommended is not enough, re-run the original at Strong rather than compressing the compressed copy a second time. Each pass loses a little more detail, and two medium passes usually look worse than one strong one.
Remove what the recipient does not need
The most effective size reduction is often fewer pages. Scanned bundles commonly include blank backs of single-sided sheets, duplicate pages and cover sheets. Take them out with Remove PDF Pages, then compress what remains — a cleaner document that is also smaller.
If the recipient needs only part of the document, send only that part. Split PDF can extract the relevant pages into a new file, which keeps text selectable and quality untouched. For a text-heavy PDF, this is often a better fix than compression, because it avoids turning the pages into images at all.
When the full document genuinely has to go and is still too large, split it into two or three parts, or share it as a link from storage rather than as an attachment. The upload troubleshooting guide covers those alternatives in more detail.
Check the result and keep the original
Open the compressed PDF and zoom to 100 percent or more on the smallest text — footnotes, table figures, a signature or a stamp. Compare the page count with the original. A file that meets the size limit but cannot be read will simply be sent back.
Check the new size in File Explorer against your target. If it is comfortably under, consider whether a lighter level would also have fitted: a cleaner-looking document is worth a few extra kilobytes when you have room to spare.
Rename the compressed copy so you can tell the two apart, and keep the original. The compressed file is for sending; the original is your full-quality record, and the one to use if the recipient later asks for a clearer copy or needs to copy text from it. On a Mac, the equivalent steps are in the Mac guide.
Open Compress PDFWorks in Edge or Chrome on Windows — no install, nothing uploaded.
Open Compress PDF →Frequently asked questions
Does Microsoft Print to PDF make a PDF smaller?
Not reliably. Re-printing creates a new file that can end up smaller, the same or larger, and it can drop links and form fields. Use a compressor designed for the job instead.
Do I need Adobe Acrobat to compress a PDF on Windows?
No. A browser-based compressor works in Edge or Chrome on Windows and processes the file on your computer without an upload or a paid subscription.
Will the text still be searchable after compressing?
Not with PDFNest’s compressor, which rebuilds pages as images. That is ideal for scans. For a text PDF, run OCR afterwards if you need it searchable, or remove pages instead.