How to compress a PDF for email — full 2026 guide.
PDF too big for email? Real provider limits, which compression preset to pick, what to do with scans, and how to keep text crisp. Concrete steps.
Almost every email provider quietly rejects files above a certain size. Gmail is the most common — 25 MB per message. Outlook 365 — 20 MB. iCloud — 20 MB. If your PDF goes above those, you have two real options: compression or splitting into smaller files. This guide is about compression.
What actually takes up space in a PDF
A PDF is not a monolith. It is made of three layers that compress very differently:
- Text and vector elements (lines, curves) — minimal space, compression barely touches them.
- Images and backgrounds — the bulk of almost all real-world PDFs. This is where the savings live.
- Metadata, fonts, search indices — small footprint, but compression cleans them up routinely.
In other words: an 8 MB PDF full of images can drop to 1.5 MB. An 8 MB PDF that is just text will stay near 7 MB, because text was already small.
Three presets — when each one fits
Screen (strongest compression)
Images drop to 72 DPI — the resolution of a regular laptop screen. They visibly lose sharpness when you zoom in. Ideal for files the recipient just needs to read on a screen and is not planning to print.
E-book (recommended)
Images at 150 DPI — the sweet spot. Looks clean on monitors and tablets, print is acceptable. This is the default for most situations: contracts, presentations, reports you send to clients.
Print (lightest compression)
Images at 300 DPI — professional print resolution. Compression is minimal but quality is 100% preserved. Pick this only when the file has to go to a print shop, or the recipient will print it themselves in colour.
What about scans
A scanned PDF (images of paper, not real text) is a special case. Each page is essentially one big image, so compression helps a lot — often 80%+ savings. Watch out though: if the scans contain important small text (signatures, stamps, dates), the "Screen" preset can blur them past readability. Stay on "E-book".
When compression is not enough
If the document is extremely large (50+ MB) or already optimised, compression will give you 5-15% and that is it. Then better options are:
- Split the PDF into 2-3 smaller files and send them in separate emails.
- Upload the file to a cloud service (Google Drive, Dropbox, WeTransfer) and email the link.
- If the images really are the important part, extract them as lower-resolution JPGs and rebuild the PDF.
How to do this here
Open the compression tool, drop the file in, pick a preset, click "Convert". We return a smaller PDF in 2-5 seconds. If the algorithm sees that the output is not actually smaller (an already-optimised PDF), we hand back the original — no quality loss, no charge.