How to reduce PDF file size on Windows — without uploading it

By the PDFClubs team · Updated 21 October 2026 · 2 min read

Why is my PDF so big?

Text is tiny inside a PDF; images are not. A ten-page contract typed in Word may be a few hundred kilobytes, while the same ten pages scanned on a phone or office scanner can be tens of megabytes, because each page is stored as a full-resolution photo. Embedded fonts and very high-resolution pictures add more.

So the fix depends on where the PDF came from.

Method 1 (free): Re-save from Word at minimum size

If you still have the original Word document, Word can make a smaller PDF directly:

1. Open the document in Word and choose File › Save As.
2. Pick PDF as the file type.
3. Under Optimize for, choose Minimum size (publishing online).
4. Click Save.

This only helps with documents you made in Word — it cannot shrink a PDF you received or a scan.

Method 2: Compress any PDF with Office File Manager

For scans, photo-heavy PDFs and files you didn't create yourself, compress the images inside the PDF:

1. Install Office File Manager from the Microsoft Store and open Compress PDF.
2. Add your PDFs, or drop a whole folder.
3. Choose one of the three compression levels.
4. Click Compress and compare the size before and after each file.

Scanned PDFs shrink the most — by up to 94% — and text and drawings are left untouched so they stay sharp. Everything happens on your PC, which matters when the PDF is a bank statement or ID document.

Method 3: Scan smaller in the first place

If you scan documents yourself, 150–200 dpi is plenty for text pages, and scanning in greyscale instead of colour makes a big difference. Save the higher settings for photos and documents with fine print.

Tips

• Email limits: Gmail, for example, accepts attachments up to 25 MB in total — compress first rather than splitting a document across emails.
• Upload forms often have strict limits. Try the strongest compression level first and check the result is still readable.
• Mostly-text PDFs are already small and won't shrink much — that's normal.

Questions

Does Windows have a built-in PDF compressor?

No. Windows can create PDFs with Microsoft Print to PDF, but it has no option to compress an existing PDF.

Will compressing make the text blurry?

Not with Office File Manager — only the images are recompressed; text and drawings are left as they are.

How much smaller will my PDF get?

It depends on the content. Scanned and image-heavy PDFs can shrink by up to 94%; text-only PDFs shrink much less.