PDF Compression

How to Reduce PDF Size for Email and Upload Portals

Last updated · By the PDFSolution team

Upload portals are unforgiving: 5 MB, 10 MB or 25 MB and not a byte more. Rather than compressing blindly, it helps to work through the possible savings in order of how much quality they cost you.

Ready to do it now? Open the tool this guide describes.

Compress PDF

Step by step

  1. 1

    Remove pages you do not need to send

    Blank scanner pages, duplicate copies and separator sheets cost nothing to remove and lose no quality at all.

  2. 2

    Compress at the Recommended level

    For most scans this alone brings the file well under a typical limit.

  3. 3

    Step up to Strong compression if needed

    Check the smallest text afterwards; readability matters more than the exact file size.

  4. 4

    Split the document as a last resort

    If the portal still refuses it, split the PDF into part 1 and part 2 and upload both.

Useful tips

  • Photographs taken with a phone are usually the single biggest contributor — replacing a 12-megapixel photo of a page with a proper scan can cut a file dramatically.
  • Zip files rarely help: PDF content is already compressed inside the file.
  • If the recipient only needs to read one section, send just that section instead of the whole document.

Common problems

The portal rejects the file without saying why
Some portals also enforce page limits or reject encrypted files. Try removing the password first if the document has one.
The file is exactly at the limit and still fails
Limits are often applied to the whole request including overhead. Aim for roughly 10% below the stated limit.

Frequently asked questions

What is a reasonable size for a scanned page?
Roughly 100-300 KB per page in greyscale at 300 DPI is normal. Much more than that suggests unnecessary colour or resolution.
Does emailing a link help?
Yes, sharing through cloud storage sidesteps attachment limits entirely, if the recipient allows it.
Will compression break a signed PDF?
Rebuilding page content invalidates a cryptographic signature. Compress before signing, not after.

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