Windows has no built-in PDF compression. Word can open a PDF and save it back smaller — sometimes. The Microsoft Store has compressors that ask for a subscription. The straightforward answer is the browser.
The Flint flow
Compress PDF in Flint via Edge or Chrome. Drag in the PDF (from File Explorer, Outlook, anywhere), pick Light/Medium/Heavy quality, download. Medium handles 90% of cases — drops file size 50–80% with no visible quality loss.
30 seconds, no install.
Why not just use Word?
Word will open a PDF and let you re-save it. The result is sometimes smaller but quality often degrades unpredictably — text reflows, images shift. Compression isn't Word's job. Dedicated tools (Flint, Acrobat) handle it cleanly.
When trimming beats compression
Sometimes the right fix is fewer pages, not smaller pages. If only pages 1–10 of a 200-page report matter, split the PDF or delete unnecessary pages first, then compress. End result is dramatically smaller.
FAQ
Will compression break OCR?
No. Compression targets embedded images. Text layers (from OCR or born-digital PDFs) preserve through compression. Searchable PDFs stay searchable.
How much can I compress without losing quality?
Medium preset usually drops 50–80% with no visible quality change. Heavy compresses further at minor visual cost — fine for archival. Light is gentle, good for client-facing work where every pixel counts.
Is there a Windows command-line option?
Yes, via tools like Ghostscript or qpdf. They work but require setup and have a learning curve. For occasional compression, browser is faster. For automated batches, command line wins.
Big PDF that won't email? Compress in the browser and try again.