Compress a PDF to Send by Email or Upload to a Portal

"Attachment too large." "File must be under 2 MB." Few messages are more annoying when you're trying to send a document. The good news is that most oversized PDFs can be shrunk a lot, because the size usually comes from just one thing: images.

Why is my PDF so big?

• Scanned pages. A scanned document is a stack of photos, one per page. High-resolution colour scans can be several megabytes per page.
• Photos. Reports and brochures with full-resolution photos from cameras or phones.
• Embedded fonts and duplicated images created by some programs.

Plain text is tiny. A 50-page text-only PDF is often smaller than one phone photo.

Compress a PDF

1. Open Compress PDF.
2. Add your PDF.
3. Choose the quality. Start with a medium setting; you'll see how much is saved.
4. Download and open the result to check that photos and scans still look fine.

Only images are re-compressed. Text and vector drawings aren't changed, so they stay perfectly sharp at any zoom level.

If the PDF is password-protected, unlock it first with the password, then compress.

Still too big? Try these

Remove pages you don't need

Scans often include empty backs of sheets. Remove Blank Pages finds them, lets you check the selection, and removes them in one go. Every removed page is a full image you no longer send.

Split the document

If a portal accepts several uploads, or your email can carry more than one message, Split PDF divides it into parts, by page ranges like 1-10, 11-20, or into equal parts. Splitting doesn't change the pages' quality.

Re-scan more sensibly

For text documents, scanning at 200–300 DPI in greyscale or black and white is plenty. Colour scans at 600 DPI are many times larger with no benefit for reading.

Know the limits you're aiming for

• Email: many services limit attachments to around 20–25 MB per message, and the recipient's mailbox may accept less.
• Online forms and government portals often have strict limits such as 1, 2 or 5 MB, stated near the upload button.
• Messaging apps have their own document limits.

Aim a little below the stated limit, so a slight difference in how sizes are counted doesn't trip you up.

What not to do

• Don't take screenshots of each page and paste them together; it makes the text blurry and unsearchable.
• Don't compress the same PDF again and again at low quality; each round can soften images further. Start from the original.
• Don't print to PDF at "smallest size" without checking: text may turn into images.

Common questions

Why did my PDF barely get smaller? If it's mostly text and vector drawings, there's little to compress: those parts are already efficient and aren't touched. Compression helps most with scans and photos.

Will the compressed file still print well? At medium settings, yes, for normal documents. For photos that will be printed large, keep the original or use a higher quality.

Can I compress a PDF on my phone? Yes. It works in mobile browsers; large files just take longer on slower phones.

Privacy matters with PDFs

The PDFs people need to shrink are often tax forms, salary slips, medical reports or contracts. The compression here happens in your browser: the document never leaves your device, which is safer than uploading it to an unknown server.

Summary

1. Compress at medium quality and check the result.
2. Remove blank pages.
3. Split if a single file is still too large.
4. Scan text documents at sensible settings.