For concatenating presentations of the same topic I use pdftk (e. g. pdftk stones\ in\ england.pdf stones\ from\ namibia.pdf cat output nice\ stones.pdf).

Files with diferent frame sizes but same aspect ratio are just stringed together without any respect to the frame sizes.

How can I concatenate multiple *.pdf with one resulting size for all frames (in the same aspect ratio)?

3 Answers 3


This doesn't answer your question directly, but it's a possible workaround to the problem.

I had this problem when trying to combine two different PDF scans together that were scanned by different parties: PDF page sizes before and after For PDF files that allow printing, you can select the "Print to PDF" option from the printers dropdown menu and use the print dialog's scaling options to adjust the size accordingly: Print to PDF dialog window In my case, I used Foxit Reader and the "Fit to printer margins" option, which scaled the page down to 22.5% of the original size. You can configure the printer to whatever paper size you need in the properties dialog window. After the new PDFs are generated, you can concatenate the pages as you would normally.

One downside to this method is that the text will no longer be selectable/searchable (it's essentially been converted to an image). The same applies to any fillable form fields/buttons/checkboxes. This is likely not an issue if you are dealing with scanned PDF pages. If you still need the text to be selectable/searchable you can use an OCR tool to recognize the text (there are free tools available online and many paid versions of PDF viewers/editors have this feature)

  • 3
    This would be a good answer had this question been asked on Super User. However, given that this site is Unix & Linux and the question itself is tagged as pdftk, answers should either involve this utility (or similar command-line tools that runs on a Unix-like OS). Commented Jan 30, 2019 at 20:02
  • I'm more concerned about portrait and landscape formatted pages in the same document. @cnachtmann So I had to pdftk burst them first...? (Obviously: yes.) ... and put them together afterwards. Seems quite manually done work and therefor not really in a fashion for people knowing how to use automation.
    – Nepumuk
    Commented Feb 8, 2019 at 22:12

Bring the constituent pdfs to proper size

I faced this issue when combining two pdfs where one of them was orginally an image which I had converted to a pdf. Solution for me was to bring the image pdf to a good size in the initial image to pdf coversion.


convert image.jpg page2.pdf
pdftk page1.pdf page2.pdf cat output merge.pdf


convert -page a4 image.jpg page2.pdf
pdftk page1.pdf page2.pdf cat output merge.pdf
  • This solved my problem. Thank you so much! Other than a4, what are the other arguments we can pass to the "page" option?
    – evaristegd
    Commented Apr 1 at 1:52

I have been looking for a scriptable solution using qpdf or pdftk, but to no avail. The closest I found uses pdfjam, which is shipped with the TeXLive package (and may be so large that you do not want to install it solely for this purpose):

pdfjam --outfile out.pdf --paper a4paper in.pdf

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .