How to Compress a PDF for Email (and When Not To)
Most email providers limit attachments to somewhere around 20–25 MB, and many company systems and online forms are stricter. A single scanned contract can blow past that. Here is how to shrink a PDF sensibly.
Why PDFs are large in the first place
A PDF is a container. Pages that were typed in a word processor store text and fonts, which takes very little space. Pages that were scanned or photographed store a picture of the page, and pictures are big. High-resolution photos, embedded fonts and unused metadata all add weight.
A simple routine
- Check the size and the source. If the file came from a scanner, expect large savings. If it was exported from Word, there may be little to gain.
- Run it through Compress PDF. Download the result and compare the size.
- Open it and zoom in. Look at small text and any signatures or stamps. If they are still readable, you are done.
- If it is still too big, remove pages you do not need with Delete PDF Pages or split it into two emails with Split PDF.
What compression changes
Compression mostly works by lowering the resolution and quality of images inside the PDF. Text is usually left as it is. That is why compressed scans can look slightly softer, while text-heavy documents look the same.
When not to compress
- Documents for printing at high quality, such as a brochure or a photo book, should keep their original resolution.
- Legal or archival originals. Keep an uncompressed copy and send the smaller one.
- Files with fine detail, such as technical drawings, where lost sharpness can change meaning.
Other ways to cut size
If a PDF has many large photos, you can extract and resize them separately: Extract Embedded Images pulls them out, Image Compressor shrinks them, and Image to PDF puts them back together. You can also convert colour pages to black and white with PDF Grayscale when colour is not needed.
Share a link instead
If the file is simply too large for email even after compression, uploading it to a cloud drive and sharing a link is often the better option.
Frequently asked questions
How small can a PDF get?
It depends on the content. Scanned and photo-heavy PDFs can often shrink by more than half; text-only documents already compact may shrink very little because there is nothing large to remove.
Will compression make my text blurry?
Real text is usually kept as text, so it stays sharp. Scanned pages are pictures of text, so strong compression can soften them. Check small print after compressing.
Is compression reversible?
No. Lossy compression discards detail permanently, so keep your original file and send the compressed copy.
What if the file is still too large?
Remove unneeded pages, split the document into parts, or share a download link from a cloud drive instead of attaching the file.
Key takeaways
- Scans compress well; typed documents do not.
- Zoom in and check readability after compressing.
- Keep an uncompressed original.
Tip: every tool page shows a ⚡ Browser or ☁️ Cloud badge. Browser tools process your file on your own device; Cloud tools upload it temporarily and delete it automatically within about an hour.