Back to blog FileSwitch guide

Compress PDF Online for Email, Forms, and Upload Limits

Reduce PDF size for email attachments, portals, mobile uploads, and online forms while keeping text readable.

Updated July 10, 2026

Upload limits are a common PDF problem

Many websites reject PDFs that are larger than their limit. The limit might be 2 MB, 5 MB, 10 MB, or another number. Compressing the PDF can help the file fit without changing the document format.

This is useful for resumes, applications, invoices, scanned pages, signed forms, reports, and client files.

Compress the final version

If you still need to merge, split, rotate, crop, or remove pages, do that work first. Compress after the document is organized. Compressing too early can make every later review harder.

For scanned PDFs, file size is often high because each page is an image. Removing blank pages and duplicate scans can reduce size before compression even starts.

Check quality after compression

Open the compressed PDF and zoom in on small text, tables, stamps, QR codes, barcodes, signatures, and ID numbers. If those details become unclear, use a lighter compression setting or remove unnecessary pages instead.

Keep the original

Do not delete the original file until the compressed PDF has been accepted by the email system or upload portal. The original gives you a clean backup if the compressed version is too low quality.

Final recommendation

Compress PDF files when size limits block upload or sharing. Review readability before sending and keep the original until the task is complete.