How to merge PDF files

Open the PDF Toolkit, choose at least two PDF files, put them in the order you want, and download the combined document. The merge runs in your browser: pages are copied from each source file into one new PDF and handed straight back, so nothing is uploaded.

Order is the only decision that matters. Files are merged in the order they appear in the list, and the page content is copied rather than re-rendered, so text stays selectable and image quality is unchanged.

Last reviewed: 2026-09-19. Checked against the tool’s own source on that date.

What "merging" actually does to your pages

A PDF page is a self-contained object: its text, fonts, images and vector drawing instructions all travel together. Merging copies those page objects into a new document and appends them in order. Nothing is rasterised, nothing is re-compressed, and no font is substituted.

That is why a merged file is usually close to the sum of the input sizes, and why the result of merging then splitting is the page you started with. It is also why merging cannot reduce file size — there is no re-encoding step in which a saving could happen.

Two things do not survive, and it is better to know now than to discover it later. Document-level bookmarks (the outline panel) are not carried across, because they belong to the document catalogue rather than to any page. Interactive form fields may lose their bindings for the same reason. Links drawn on a page are page annotations and are copied with the page.

Doing it

If any file is password-protected, the tool reports it instead of opening it. Removing an access control is not something this toolkit does, deliberately. Unlock the file in the application that protected it, then merge the unlocked copy.

  1. Open the PDF Toolkit and select "Merge PDFs".
  2. Add every file you want combined. Fewer than two is refused, with a message saying so, rather than silently producing a copy of the one file.
  3. Check the order in the list. That is the order the pages will appear in.
  4. Merge, then download. The file is written in your browser and saved straight to your device.

Getting the order right the first time

Most merge mistakes are ordering mistakes, and the usual cause is filenames that sort differently from how you think. "Scan 2.pdf" and "Scan 10.pdf" sort with 10 before 2 in almost every file picker, because the sort is alphabetical rather than numeric.

Zero-padding the names before you start — "scan-02.pdf", "scan-10.pdf" — makes the picker order match the human order, and costs less time than reordering afterwards.

If a single page is out of place in the merged result, you do not need to merge again. Use "Reorder pages" on the output, which moves pages within one document.

Worked example: one PDF from a three-part application

You have three files to send as one document: a two-page covering letter (letter.pdf), a four-page CV (cv.pdf) and a one-page reference (reference.pdf). The recipient wants a single attachment.

  1. Select Merge PDFs and add letter.pdf, cv.pdf and reference.pdf, in that order.
  2. Confirm the list reads letter, CV, reference top to bottom.
  3. Merge and download.

Result: A single seven-page PDF: pages 1-2 are the letter, 3-6 the CV, 7 the reference. Text in all seven pages is still selectable and searchable, because the pages were copied rather than re-rendered.

Open the tool

Merge PDFs in the PDF Toolkit

Runs in the browser, needs no account, and will refuse an encrypted file rather than attempt to open it.

What this does not cover

  • Merging cannot reduce file size. The output is roughly the sum of the inputs, and this toolkit has no compression feature at all.
  • Password-protected or encrypted PDFs are reported rather than opened. No access control is removed.
  • Document outlines (bookmarks) and form-field bindings are not carried into the merged file.
  • Everything is held in your device memory, so a very large batch on a phone will be slower and can run out of room.