A PDF that bounces from email is almost always a size problem, not a format problem. This guide covers the attachment limits that actually bounce your mail, why scanned PDFs get so heavy, and how to shrink one to 100–300 KB without losing a single page.
⚡ Skip the reading — compress now
Free targets: 100 KB / 200 KB / 300 KB. All pages safe, nothing deleted, processed in your browser.
📄 Open PDF Compressor →📬 Limits that bounce your mail
Gmail — 25 MB per mail (all attachments together)
A single 26 MB PDF bounces the whole mail. Compress first, then attach.
Outlook / Hotmail — Around 20 MB per mail
Outlook is stricter than Gmail — aim well under 20 MB, not just under it.
WhatsApp document — Large files upload slowly on mobile data
A 2 MB PDF sends in seconds; a 40 MB scan can stall. Compress even when it is technically allowed.
Office / HR portals — Often 2–10 MB per file
Resume and certificate uploads usually cap at a few MB — 200–300 KB is the safe zone.
🔍 Why is your PDF so heavy?
- •Phone scans at full resolution: a colour scan at high DPI makes every page a multi-MB photo. This is the #1 reason PDFs get heavy.
- •Colour where greyscale would do: a black-and-white document scanned in colour is 3–5× bigger for zero extra information.
- •Embedded fonts and images: PDFs exported from design apps carry heavy fonts and images you never see.
- •No compression on export: some scanners and apps save PDFs uncompressed by default.
📝 Compress in 4 steps
- 1.Check the size first: on your phone, long-press the PDF and look at its size. Anything above 5 MB deserves compression before emailing.
- 2.Open the free PDF compressor below and upload the PDF. It runs in your browser — the file is never sent to a server.
- 3.Pick a target: 100 KB for forms, 200 KB for email, 300 KB when the PDF has fine print you must keep sharp.
- 4.Download and open every page once: check that no page is missing and small text is still readable. The compressor never deletes pages, but this 10-second check saves a second mail saying 'sorry, resending'.
❓ Common questions
Will compression delete pages from my PDF?
No. The compressor shrinks the photos inside the PDF — every page stays, in order, with the same text. Only the image quality is reduced to hit your target size.
What target size should I pick for email?
200 KB is the sweet spot for email: small enough to pass every limit, sharp enough to read. Use 100 KB for strict forms and 300 KB for fine-print documents.
My scanned PDF is 40 MB. Can it really become 300 KB?
Often yes, if the bulk is scan photos. Colour scans compress dramatically. If the result looks blurry, step up to a bigger target instead of forcing 100 KB.
Is my PDF uploaded anywhere?
No — your PDF file itself is never uploaded. It is processed inside your own browser. Only the PDF engine script loads (the site's own copy first, otherwise a public CDN copy); no file content leaves your device.