Optimize PDF files
Optimizing changes how a PDF is stored rather than what it says: a smaller file for an email or upload form, pages resized for a different paper size, or a damaged file saved again so it opens. Everything happens on your device.
Optimize PDF- Compress PDF
Make a PDF smaller, to a size you choose, with text kept sharp.
- Repair PDF
Fix a damaged PDF that will not open, and see what was wrong.
- PDF to PDF/A
Convert a PDF to PDF/A-1b, 2b or 3b for archiving, checked against the rules first.
- Resize PDF
Change PDF page size to A4, Letter or a custom size, or put several pages on one sheet.
- PDF Poster
Print a PDF page as a big poster across several sheets, with overlap for gluing.
Why is my PDF so large?
Large PDFs nearly always contain large images: scans saved at high resolution, phone photos, or slides with pictures. Text takes very little space. Making a PDF smaller mostly means storing those images at a lower resolution or stronger compression. Fonts can add a little too, when a file carries whole font families instead of only the letters it uses.
Will compressing make my PDF blurry?
A little compression is hard to see on screen. Strong compression makes photos soft and can make small scanned text harder to read. The compress tool shows the new size before you download, so you can step back if the result looks too rough.
A4 or Letter: what is the difference?
A4 (210 by 297 mm) is used in most of the world. US Letter (8.5 by 11 inches, about 216 by 279 mm) is used in the United States and Canada. Resize PDF converts between them and scales or pads each page so nothing is cut off.
Can a damaged PDF be fixed?
Sometimes. If the file was cut short or saved with errors, rewriting its structure can make it open again. If the data itself is missing, no tool can bring it back, and the repair tool says so. Keep the original file either way, in case another program can read more of it.
Guides
- Why Is My PDF So Large? What takes up the space in a PDF, measured, and how to fix each cause.
- Email Attachment Size Limits for PDFs Each provider's limit from its own help page, and why a PDF grows 37% inside an email.
- PDF Compression Test Five kinds of PDF at every compression level: size saved and whether text stays readable, with CSV data.
- PDF Too Large to Upload? Real scans pushed toward 5 MB to 100 KB limits: what fits, and what to do when compression is not enough.
- How to Compress a PDF on iPhone Shrink a PDF in Safari with no app or upload; a 7.8 MB scan came down to 559 KB.