Merge PDF

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Combine multiple PDF files into one in your browser. Free, fast, and private — files never leave your device.

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Runs in your browser — your file never leaves your device.

Combine two or more PDFs into one document without uploading anything. Merge PDF opens your files inside the browser tab, copies every page into a new document in the order you listed them, and hands the result straight back — there is no server round trip, no queue, and no watermark on the output. Because pages are copied rather than re-rendered, text stays selectable and images keep their original resolution, so the merged file is as good as the originals. Nothing is uploaded, nothing is stored, and no account is needed.

How to use Merge PDF

Click "Select PDF files" and pick two or more PDFs, or drop them onto the page.
Check the order in the "Your file(s)" list. Files are joined from the top down, in the order you added them — use "Add more" to append another file, or a card's remove button to take one out.
Click "Merge PDFs". Everything runs on your own device, so speed depends on your computer rather than on an upload.
Download merged.pdf.

Who it is for

Merge PDF is for the everyday job of assembling one document out of several: a report made of separately written chapters, a job application of CV and covering letter and certificates, scans of a contract photographed one page at a time, or a month of invoices that has to become one file for the accountant. It is also the tool to reach for before posting a scanned bundle anywhere, because putting the pages in the right order is easier here than in any reader. If you are sending a file that contains personal information — a passport scan, a medical letter, a signed agreement — this is one of the few merge tools where that file genuinely does not leave your computer, which is usually the reason people look for an alternative to the big sites in the first place.

How it works

Each PDF is opened by pdf-lib, a JavaScript library the page loads once. The library reads the file's internal object table, finds every page, and copies those page objects into a brand-new empty document in the order you arranged. Nothing is photographed or run through a printer driver, which is why a merged page is byte-for-byte the same content as the original page.
Because the pages are copied rather than re-rendered, the things that make a PDF searchable survive: the text layer, the embedded fonts, the vector lines, the images at their original resolution. A merge done this way cannot add the softening you see when a tool rasterises pages to a picture.
Everything runs in the tab, so there is no upload step and no server holding a copy while you wait. That also explains the trade-offs below: your computer's memory is the real limit, not a server quota.

What it cannot do

Bookmarks and interactive form fields are not rebuilt in the merged file, even though the page content is. If a form already contains values you need, flatten it first so the values become part of the page.
A single file over 100 MB is skipped with a message rather than attempted, because loading it would exhaust the tab's memory and freeze the page. Very large merges need a desktop-class machine; a phone will give up sooner.
Encrypted PDFs cannot be merged, because their pages cannot be read until the password is removed. Unlock a file you own first, then merge the unlocked copy.
The order is the order you added the files. There is no drag-to-reorder, so changing the sequence means removing a card and adding the file again.

Frequently asked questions

Are my PDFs uploaded anywhere?

No. The merge is done in your browser by pdf-lib, a JavaScript library the page loads once. Your files are read from disk into the tab's memory, never sent to us, and gone as soon as you close the tab.

How many files can I merge, and how large can they be?

There is no limit on the number of files. Each individual file should be under 100MB — past that the browser is likely to run out of memory, so the tool skips it instead of freezing. There is no daily limit and no sign-up.

Does merging lose quality or add a watermark?

Neither. Pages are copied object for object into the new file, so text stays selectable and searchable, images are not recompressed, and nothing is stamped onto the output.

Can I reorder the files after adding them?

The merge follows the order in which you added the files. To change it, remove a file with the button on its card and add it again in the position you want.

My PDF is password protected and it will not load.

Encrypted PDFs have to be decrypted before their pages can be copied. Take the password off first with the Unlock PDF tool, then merge the result.

What happens to bookmarks and fillable form fields?

Page content — text, images and links — carries across. Document-level extras like bookmarks and interactive form fields are not rebuilt in the merged file, so if a form already holds values you need to keep, run it through Flatten PDF first to fix them onto the page.

Can I merge pages from the middle of a large PDF without splitting it first?

Yes, in two steps: split out the pages you want with Split PDF or Extract Pages, then merge those parts with the rest. That keeps the intermediate files small, which matters on a machine with limited memory.

Why is the merged file slightly larger than the individual files added together?

Each source file carries its own structural overhead — fonts, colour information, page instructions — and the merged document keeps what each page needs. Shared resources are not deduplicated across the inputs, so a few percent of growth is normal and harmless.