How to Compress a PDF Under 10 MB (Without Ruining It)

"Attachment exceeds the maximum size." Whether it's a visa application portal capped at 5 MB, a court filing system at 10 MB, or plain old email at 25 MB, PDF size limits always appear at the worst possible moment. The good news: most oversized PDFs are oversized for one specific, fixable reason.

Why is your PDF huge?

Text is essentially free — a 300-page novel as a text-only PDF is about 2 MB. What bloats PDFs is images: scanned pages stored as full-resolution photos, phone-camera "scans" at 12 megapixels each, or slide decks exported with uncompressed screenshots. One scanned page at 600 DPI can be 5 MB on its own. That's why a 20-page scan can weigh 60 MB while a 200-page contract weighs 1.

Method 1: Compress the whole document

FileLark's PDF compressor re-renders every page at a sensible resolution and re-encodes it as an optimized JPEG — the same technique "print to PDF at reduced quality" uses, but in one step and entirely in your browser (nothing is uploaded, which matters for the contracts and medical records people most often need to shrink). Scanned and image-heavy documents routinely drop 70–90%: a 40 MB scan becomes 4–6 MB at the Balanced preset. One honest caveat: because pages are re-rendered as images, text in the output is no longer selectable — irrelevant for scans, worth knowing for born-digital documents.

Method 2: Remove what you don't need

Often the fastest win isn't compression — it's scope. If the portal wants "pages 12–14 of your bank statement", don't upload all 40 pages: extract just the range you need. Blank scanner pages and duplicate sheets can be dropped with the page editor. Cutting a document from 40 pages to 3 shrinks it proportionally with zero quality loss.

Method 3: Rebuild from better sources

If your PDF was built from photos, compress the images first, then rebuild. Run the photos through the image compressor with a target of 150–200 KB each, then combine them with images to PDF. Ten photos × 200 KB gives you a 2 MB document with quality that's indistinguishable on screen.

Hitting a specific number

Aim below the limit, not at it — portals often measure size differently than your file manager (megabytes vs mebibytes), so treat "10 MB" as "9 MB". Start with the Balanced preset, check the before/after size shown, and step up to Strong only if needed. For extreme targets, combine methods: extract the required pages first, then compress the result. And always keep your original — compression is a one-way street.