How to change the modified date of a PDF

Why Finder and a PDF viewer can show different dates

Finder reads the modification time of the file on disk. PDF applications can read an internal ModDate property or XMP metadata. Changing a filesystem timestamp alone does not update the date stored inside the PDF.

Some PDFs contain both Info and XMP dates. If only one is changed, applications reading the other may continue to show an older value. WordDate writes and verifies the supported standard date fields together.

Change a PDF’s last modified date

1. Finish any PDF edits, close the file in your editor and add it to WordDate.
2. Enable Set dates separately so you can choose a modified date independently of Created.
3. Set the Modified date and time. Check Created too; it must not be later than Modified.
4. Review the Finder and PDF values under After applying. Check whether you want optional additional date properties updated.
5. Select Save a copy or Update original, then click Apply dates.
6. Re-add the saved output to inspect the embedded values, and use Finder’s Get Info to check the file timestamp.

What changes inside the PDF?

WordDate sets the standard Info CreationDate and ModDate fields to your selected created and modified values. It also updates standard XMP CreateDate, ModifyDate and MetadataDate fields, adding missing standard date fields where needed.

It does not render the PDF into images or flatten its pages. Text, form fields, annotations, links and attachments are retained. Dates in page text, embedded objects and unrelated XMP namespaces are outside this date-editing task.

Why a PDF date can change again

A PDF editor may set new modification metadata when it next saves. Copying, downloading and synchronising can also affect Finder timestamps. Apply your intended date values after finishing content edits, then check the copy you will use.

WordDate supports PDFs up to 256 MB and rejects encrypted or digitally signed documents. It replaces dates; it does not remove them or erase a file’s history. If deletion is your goal, see the separate PDF modified-date removal guide.