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How to compress a PDF so it's small enough to email

"Your attachment exceeds the limit" — almost always a PDF full of scanned pages or photos. This guide explains why PDFs get so big, what compression trades off, and how to shrink one in your browser so it fits, without uploading the document anywhere.

The fastest way

Open Compress PDF, drop in your file, pick a quality, and download the smaller result. Done.

Why PDFs get huge

It's the images. A PDF of typed text is tiny; a PDF made from a phone scan or packed with high-resolution photos stores all those pixels, and that is what pushes it to tens of megabytes. So compression targets the images — that's where the savings are.

What compression trades off

Compress PDF re-encodes the embedded images at a lower quality or resolution. Text remains crisp; images get slightly softer. For sending a scanned contract, a receipt, or a report, the drop is usually invisible and the size win is large. Pick a stronger setting for a smaller file, a gentler one to keep more detail.

If it's still too big: split it

Compression has limits. If you only need part of the document, use Split PDF to pull out the pages you actually need — a short range is far smaller than the whole file. And if you over-split, Merge to PDF joins pieces back together.

A note on privacy

Contracts, statements, scanned IDs — PDFs are often sensitive. Compress PDF works entirely in your browser, so the file is never uploaded and nothing is left behind when you close the tab.

Open the Compress PDF tool →

Common questions

Why is my PDF so large?

Usually because of images. A PDF made from phone photos or a scanner stores high-resolution images, which dominate the file size. Text-only PDFs are small; it's embedded images and scans that make a PDF tens of megabytes.

What does compressing a PDF actually do?

It re-encodes the embedded images at a lower resolution or quality, which is where almost all the size is. Text stays sharp. You trade some image fidelity for a much smaller file — fine for most documents and scans you need to send.

What if it's still too big after compressing?

Split it. If you only need some pages, use a split tool to extract just those — a 5-page range out of a 200-page PDF is far smaller than compressing the whole thing. You can also compress, then split, for the smallest result.

Is my PDF uploaded to compress it?

No. The PDF is read, re-compressed, and written entirely in your browser, so confidential documents are never sent to a server and the tool works offline once loaded.