Why upload portals have size limits
Application forms, visa and tax portals, and email providers often cap attachment size to protect their storage and keep uploads fast. The limit is set by each site, so check the one you are using. A phone scan or a PDF with full-resolution photos can easily be several megabytes.
How it works
In Keep text sharp mode the tool finds the photos and scans inside your PDF, re-encodes them as JPEG at a lower quality and resolution, drops thumbnails and metadata, and repacks the file. Text and vector graphics are left alone, so they stay sharp and selectable. It tries several quality levels and keeps the sharpest one that fits your target.
In Smallest mode every page is drawn to a picture and rebuilt as a new PDF. That gives the smallest files, but text can no longer be selected or searched.
Tips for smaller PDFs
- Scan at 150 DPI instead of 300 or 600. Text is still readable and files are far smaller.
- Scan in grayscale when colour does not matter.
- Export from Word or Google Docs instead of printing a photo of the page.
- Split a long document if one file has to stay small and readable.
What can't be compressed
A PDF that is mostly text and embedded fonts is already small, so there is little to remove. Images stored in formats this tool does not touch (for example CMYK JPEGs, or images with unusual filters) are left as they are. If Keep text sharp cannot reach your target, the tool says so and offers Smallest mode instead of pretending it worked.
Questions
Is my PDF uploaded anywhere?
No. The PDF is opened and compressed in your browser. The page blocks network requests to other sites, so the file never leaves your device.
Will the text still be selectable?
In Keep text sharp mode, yes. In Smallest mode every page becomes an image, so text cannot be selected or searched.
Can it compress a password-protected PDF?
Yes, if you know the password. You are asked for it when you open the file, and the compressed PDF is saved without a password.
What if the target size isn't reached?
The tool tells you it was not reached and shows the size it did get. You can then try Smallest mode, pick a bigger target, or split the document.