You write the email, attach the PDF and get a message saying the file is too large. It happens all the time with scanned documents, reports full of photos and anything exported from a phone. The good news: most of these files can be made much smaller without making them hard to read.
Why your PDF is so big
Text takes up almost no space in a PDF. A 50-page report with only text is often well under 1 MB. What makes a PDF heavy is images:
- Scanned pages. Every scanned page is a photo of the paper. Scanners often save them at a very high resolution.
- Photos. A single photo from a modern phone can be 3–5 MB. Ten of them in a document and you are past most email limits.
- Images saved without compression. Some programs put pictures into the PDF in a lossless format that is much larger than it needs to be.
So the way to shrink a PDF is to make its images smaller, while leaving the text alone.
How big can an email attachment be?
Most email services allow somewhere between 20 and 25 MB per email: Gmail and Yahoo allow 25 MB, and Outlook.com allows 20 MB. Many company email systems set a lower limit, often 10 MB.
There is a catch: email encodes attachments in a way that makes them about a third larger on the way. So a 20 MB file can fail on a 25 MB limit. To be safe, aim for under 15 MB, or under 7 MB if you are sending to a company address.
How to compress a PDF in your browser
- Open Compress PDF and choose your file. You will see its current size and number of pages.
- Leave the level on Recommended. It recompresses photos and scans at good quality and keeps text and drawings exactly as they are.
- Click Compress PDF. You will see the size before and after and how much you saved.
- If the result is small enough, download it. If not, try Smallest file, which shrinks images further.
The file is processed inside your browser tab, so it is never uploaded. That matters when the PDF is a contract, a bank statement or anything with personal details.
Tip: Before you delete the original, open the compressed file and zoom in on a photo or a small print area. With Smallest file, images can get a little softer.
How much smaller will it get?
It depends on what is inside:
| What the PDF contains | Typical saving |
|---|---|
| Scanned pages | 50–90% |
| Report with many photos | 40–80% |
| Mostly text and charts | 0–10% |
If your file is mostly text and is still too big, compression is not the problem. Look at the other options below.
Still too big? Four other fixes
Remove pages you do not need. Covers, blank pages and appendices add up. Use Delete PDF Pages to send only what matters.
Send only part of the document. If the reader needs one section, extract those pages into a new file.
Split it into two emails. With Split PDF you can cut a long document into parts, for example pages 1–40 and 41–80, and send each part on its own.
Scan at a lower resolution next time. For documents you only need to read on screen, 150 dpi is plenty. 300 dpi is only needed for printing, and 600 dpi makes huge files.
Quick checklist
- Aim for under 15 MB (under 7 MB for company email).
- Compress with Recommended first, then Smallest file if needed.
- Check that the compressed file is still easy to read.
- If it is still too big, remove pages or split the file.