How it works : Merge PDFs
Drop your PDFs in together. The tool stacks them end to end in the order you can see on screen, and hands you back a single file. None of the documents ever leaves your device.
Putting together pages that arrive in pieces is the most ordinary chore of office life: a contract scanned in three goes, receipts to attach to an application, payslips to staple. The gesture is simple, and it has no reason to travel through a stranger's server.
It is in fact the case where sending is most awkward: the documents people merge are almost always the ones they show to nobody. A lease, an identity document, a bank statement, a medical file. Here the files are read inside the tab, assembled in the tab's memory, and the result is handed to you by the browser.
Order is the only thing that really matters in a merge, and it is what goes wrong most often. The tool numbers every document on screen, in the order it is about to stack them, and lets you switch to alphabetical order in one click: that is the order scanners and cameras produce.
How it works
- Drop all your PDFs in at once, or pick them together in your device's file window. You need at least two.
- Each file takes its own line, with its page count. A file that is not a PDF, or that is password protected, says so on its line: the rest carries on.
- Choose the order (the order you dropped them in, or alphabetical by file name), then click “Merge and download”. The file you get lands in your downloads.
Formats accepted
PDFs only, and that is deliberate: putting an image into a PDF is a different gesture with settings of its own. The “Images to PDF” tool in the same corner handles that.
PDF document
Any PDF readable without a password. Pages are COPIED across as they are, with their fonts, their images and their dimensions: nothing is re-encoded, nothing is recompressed, nothing is redrawn.
Its limits
80 MB per file dropped
Every document is opened ENTIRELY in memory, and the merged document lives in memory alongside it. An entry-level phone has only a few hundred megabytes to lend a tab: beyond that the tab is killed by the system, and a killed tab hands back nothing. The limit is announced rather than discovered.
A password-protected PDF will not open here
An encrypted document has to be decrypted before it can be read, and that needs its password. The “Password-protect a PDF” tool in the same corner can unlock it if you have the password: go through that first, then come back and merge.
The merged document inherits no identity card, unless you ask for it
Copying the title and author of the first document onto a file that contains five would be a lie by inheritance: the card would describe a document that no longer exists. So by default it is EMPTY. A checkbox lets you carry over the first document's card when that is exactly what you want.
An electronic signature on the original does not survive the merge
A signature seals a whole file: change one byte and it no longer verifies. This is not a limit of this tool but a property of the signature itself, and no tool, local or online, can do otherwise. Keep the signed original alongside.
The drop order depends on your device
When you select several files at once, it is the system that decides the order in which it hands them to the browser, and it does not always follow what you see in your folder. That is why the tool DISPLAYS the numbered order before acting, and offers alphabetical order.
Questions about this tool
Are my documents sent anywhere?
No, and you can check in thirty seconds. Open your browser's inspector with the F12 key, go to the “Network” tab, clear the list, then drop your files and merge. Not a single line appears. You can also cut your connection: the tool keeps working, because all the code it needs is already in your browser.
In what order are the pages stacked?
In the numbered order the tool shows before acting, not in a guessed order. That number comes from the order in which your system handed the files to the browser, which is not always the order in your folder. If the order shown does not suit you, switch to alphabetical: it compares numbers as numbers, so scan-2 comes well before scan-10.
Does the quality drop?
No, and there is nothing to set for that. Pages are not redrawn or recompressed: they are copied from one document to another with their fonts, their images and their dimensions. The file you get weighs roughly the sum of the original files, give or take a few kilobytes, and that is the sign that nothing was touched.
Why does the file I got have no title and no author?
Because that would be false information. A PDF carries an identity card, and if we copied the first document's card onto it, the file would claim to be that first document while containing five. A checkbox lets you carry the card over when that is really what you want, for instance a report followed by its appendices. The “Clean a PDF's metadata” tool in the same corner also lets you control what a document says about you.
One of my PDFs is password protected.
It cannot be merged as it is: an encrypted document has to be decrypted first, and that needs its password. If you have it, go through the “Password-protect a PDF” tool in the same corner, which also unlocks, then come back here. The tool tells you clearly on the line of the file concerned, and it carries on with the others.
Can I merge fifty documents at once?
Technically yes, but the tab's memory is the real limit: every document is opened in full, and the result lives beside it. On a computer, a few dozen normal-sized files go through without trouble. On a phone, work in batches and then merge the batches: the result is identical.
What if one of my files is electronically signed?
The signature will not survive, and no tool can change that. A signature seals a whole file: modify one byte and it no longer verifies. This is not specific to this tool or to working locally. Keep the signed original aside, and use the merge for the working copy.
Drop your PDFs in together. The tool stacks them end to end in the order you can see on screen, and hands you back a single file. None of the documents ever leaves your device.
VerifyThe proof, step by stepThe network inspector check, explained one gesture at a time, with screenshots.
The cornerThe PDF cornerMerge, split, sign, fill, slim down. A PDF should never have to travel to a stranger to be cut in two.