Free Compress PDF
Make a PDF smaller for email and uploads. Choose a light clean-up that keeps text, or a stronger mode for scanned files.
Shrink a PDF so it fits an email or an upload limit. The light mode keeps your text selectable, and the strong mode rebuilds each page as a compressed image, which helps most with scans and photos.
How to use the Compress PDF
- Add your PDF. Choose the file you want to shrink. You will see its current size straight away.
- Pick a mode. Start with light mode. If the file is still too large, switch to strong mode and choose a quality level.
- Compare and download. The result shows the new size next to the old one. Download it only if it is smaller and still looks right.
What is the Compress PDF?
Email limits and upload forms often cap attachments at 5 or 10 MB. A PDF full of scans or photos can easily be bigger than that, even when it only has a few pages.
This tool offers two ways to shrink it. Light mode tidies the file structure and keeps your text selectable, which is enough for many documents. Strong mode rebuilds each page as a compressed image, which cuts the size of scanned files a lot but turns the text into a picture. Your file stays in your browser the whole time.
Why PDF files get so big
A PDF is a container. Text takes little space, but photographs, scans and embedded fonts can take a lot. A ten-page contract with text only may be 100 KB, while ten scanned pages at high resolution can be 20 MB or more. That is why a scan is often the file that will not attach to an email.
Light mode or strong mode?
- Light mode tidies the structure of the file and keeps your text. It is fast, safe for contracts and forms, and often saves a little or a lot depending on what is inside.
- Strong mode turns each page into a compressed image. It makes scanned or image-heavy files much smaller, but the text can no longer be selected or searched.
Start with light mode. If the file is still too big, try strong mode and check the result before you send it.
Size limits you may run into
Many email services limit attachments to about 20 to 25 MB, and Gmail allows up to 25 MB. Government portals, job sites and visa or university forms often set lower limits such as 2, 5 or 10 MB. Check the limit before you compress, so you know how small the file needs to be.
When not to compress
Do not replace the original of a legal or official document with a compressed copy. Keep the original, and send the smaller copy when a size limit requires it. Look through the compressed file for small print, stamps and signatures before you send it, because strong compression can make them harder to read.
Other ways to reduce size
- Remove pages you do not need with Delete PDF Pages
- Split a large file into parts with Split PDF
- Shrink the photos before you build the PDF with the Image Compressor and Image to PDF
Tips for better results
Try light mode first because it keeps text searchable and selectable.
For scanned documents, strong mode at medium quality usually gives the biggest saving with readable text.
Look through the compressed file before you send it, especially pages with small print or signatures.
Related tools
Privacy and where your data goes
Documents and files you use here are processed on your own device. Signplify does not receive what you type or the files you open, which makes it suitable for sensitive information. If you clear your browser data, any saved draft is removed. Last updated: October 26, 2026.
Frequently asked questions
Why is the file not much smaller in light mode?
Light mode only reorganises the file. If most of the size comes from large images, the saving is small, and strong mode is the better choice.
What does strong mode do to my text?
It turns each page into an image, so text can no longer be selected or searched. Use it for scans or when size matters more than searchable text.
Is my PDF uploaded?
No. Compression runs in your browser and nothing is sent to our servers.
What is the difference between the light and strong modes?
The light mode keeps your text selectable. The strong mode rebuilds each page as a compressed image, which helps most with scans and photos.
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