You go to attach a PDF and the email bounces back: "attachment too large." Most email services cap attachments at around 25 MB, and some at 10 MB. Scanned documents and image-heavy PDFs blow past that easily. The fix is to compress the PDF — reduce its file size so it fits — without paying for software.
Why PDFs get so big
Most oversized PDFs are heavy because of images — scanned pages, photos, or high-resolution graphics. A PDF that's mostly text is usually small; one built from phone photos of documents can be enormous. Compression works by re-saving those images at a sensible resolution and quality for on-screen reading.
Step by step
- Open the Compress PDF tool and upload your file.
- Pick a level. "Balanced" is the recommended starting point — a big size drop with quality that's fine for reading and printing. Choose "Maximum" if you need the smallest possible file and can accept softer images.
- Compress and check the result. The tool shows the original size, the new size, and the percentage saved.
- Download and attach it to your email.
If it's still too big
- Try the "Maximum" level for a smaller file.
- Split the document. If you only need to send part of it, use our Split PDF tool to pull out the pages you actually need.
- Send a link instead. For very large files, upload to a cloud drive and email the link rather than the file.
A note on quality
Compression is a trade-off: smaller file, slightly softer images. For everyday documents, contracts, and forms, "Balanced" is invisible to the reader. Only drop to "Maximum" when the file size truly must be tiny — and always keep your original, since compression can't be undone.
FAQ
Will compressing change the text?
No — text stays sharp and selectable. Compression mainly affects embedded images.
Is my file private?
Your PDF is processed to create the result and the temporary copy is removed automatically afterwards. See our Privacy Policy for details.
Need to combine files first?
If you're emailing several PDFs, merge them into one with our Merge PDF tool, then compress the combined file.