Sometimes a portal accepts only one attachment and your paperwork is spread across several PDFs. Sometimes the documents have simply arrived from different people and need to be put into a sensible order before they are sent.
A merge tool solves the basic problem in seconds. Before you send the result, though, there are a few things worth checking.
The quickest way to merge PDFs
Use a tool that lets you see the pages before creating the final file.
With our free PDF tool, you can add several PDFs, view all of their pages together, drag them into the right order, remove anything you do not need and export one document.
The processing happens locally in your browser, so the PDFs are not uploaded to Tangled Design's servers.
For ordinary documents, that is usually all there is to it.
Check the page order rather than trusting the import order
When several files are selected together, do not assume they will appear in exactly the order you want.
The order can depend on the platform, file picker and application.
A visual page list is much more reliable. If you are assembling an application or a case file, you can put the cover form first, supporting documents next and appendices at the end without renaming the source files.
It also makes blank or duplicate pages much easier to spot.
The final file size may change
Merging three 2 MB PDFs does not guarantee a final file of exactly 6 MB.
PDFs contain fonts, images, metadata and other resources, and different tools handle those resources differently when creating the combined file. The result may be close to the total size of the originals, smaller or larger.
If the final PDF also has to meet an upload limit, merge first and compress the finished document afterwards.
That gives you the actual file you need to send and avoids compressing several documents individually when it may not be necessary.
Be careful with digitally signed PDFs
A digital signature is tied to a particular version of a document.
If pages from a signed PDF are inserted into a new combined PDF, do not assume that the new file carries the same signature status as the original.
Where signature validation matters, keep the signed original. If you are submitting qualified or otherwise important signed documents, follow the requirements of the organisation receiving them rather than replacing the originals with a merged copy.
You can still make a combined PDF for convenience or reference, but it should not automatically be treated as a substitute for the signed source files.
Forms and interactive features need a quick check
A PDF can contain more than visible pages.
It may also include:
- fillable form fields;
- bookmarks;
- links between pages;
- comments and annotations;
- scripts or other interactive elements.
Merge tools do not all preserve these features in the same way.
If the source files contain anything interactive, open the finished PDF and test it before sending.
For ordinary PDFs made up of text and images, this is much less likely to matter.
Merging does not require turning pages into images
There is no technical reason a normal PDF merge has to rasterise every page.
If the source PDFs contain selectable text, a tool that preserves the original page content can keep that text searchable and selectable in the combined file.
After export, try selecting a sentence or searching for a word if this matters for your document.
That quick check is especially useful for reports, contracts and accessible documents.
Avoid using Print to PDF as a merging method
Printing documents into a new PDF can appear to achieve the same result, but it takes the files through a different workflow.
That process can discard information that is not part of the visible printed page, including links, bookmarks, form fields, annotations or accessibility structure.
If all you need is to place existing PDF pages into one document, use a proper merge function instead.
Remove blank and duplicate pages before exporting
Scanned documents sometimes contain blank pages, and files collected from several people can contain the same attachment twice.
A page overview makes these easy to catch.
Before downloading the final file, scan the thumbnails once and remove anything that should not be there.
A 30-second check before you send it
Before uploading or emailing the merged PDF:
- check the first and last page;
- scan the thumbnails for the correct document order;
- remove blank or duplicate pages;
- confirm that text is still selectable if searchability matters;
- test forms and links if the originals contained them;
- keep the originals of digitally signed documents;
- check the final file size.
That is usually enough.
If the PDFs contain sensitive information
Merging documents does not necessarily require sending them to a remote server.
Contracts, ID documents and files containing personal data can be combined locally when the tool performs the work in the browser.
Our PDF tool does exactly that. The files stay on your device while you merge them, reorder pages or remove pages you do not need.
In short
The merge itself is the easy part.
Check the page order before export rather than relying on the order in which files were imported. If you have a size limit, compress the final merged PDF rather than guessing from the size of the source files.
And if the documents include forms, links, annotations or digital signatures, verify those features separately. Their behaviour depends on the PDF and the tool used to combine it.
