Compress a PDF for CAO
CAO takes PDFs up to 5 MB. PDF Desk shrinks yours to just under it, right in this tab.
Max 5 MBPDF / JPG / PNG / TIFF
Files stay on this device. Nothing is uploaded.
CAO (Central Applications Office) upload limits
| Document | Max size | Min size | Formats |
|---|---|---|---|
| Supporting document upload (per file) For qualifications in Categories 3-7 and Advanced Entry; HEAR/DARE paperwork, disability evidence and GEM transcripts must be posted, not uploaded. | 5 MB | — | PDF, JPG, PNG, TIFF |
Where this number comes from
“Size: Max 5MB per file”
— Upload Your Supporting Documents | CAO. Checked October 2026.
PDF Desk aims at 4.8 MB, a little under the limit, because some portals count 1 KB as 1,000 bytes.
If the file will not get small enough
Scan in black and white at 150 DPI instead of colour. Remove blank and duplicate pages with Delete pages. If the portal allows several files, cut the PDF with Split PDF and upload the parts.
Limits of other portals
Questions
What is the maximum PDF size for CAO?
Supporting document upload (per file): 5 MB. Source: cao.ie, checked October 2026.
CAO still rejects my PDF. Why?
Check that it is not password-protected, that the file name has no special characters, and that it is a few percent under the limit — some portals count 1 KB as 1,000 bytes.
Are my PDFs uploaded?
No. PDF Desk opens and writes the file with JavaScript inside your browser tab. Nothing is sent to a server, so it is safe for contracts, IDs and bank statements.