Merge PDF

Merge PDF: set the order, pick the pages, and check the merged document before you save

Merging PDFs means joining the pages of several PDFs, in the order you choose, into a single file. As soon as you add files, this tool shows two things together. The file list at the top is where you set the order and choose which pages to use from each file, and the preview below shows the pages of the merged document in their real order. Click a page in the preview to drop it, and the pages field in the list changes with it.

For example, the 3 sample PDFs (a 2-page application form, a 1-page certificate and a 5-page portfolio, 45 KB in total) merge as they are into one 8-page file (38 KB), with 3 bookmarks named after the files and the portfolio's own 5 bookmarks nested underneath. Pages are copied from the originals as they are, so text stays text you can search and copy, and page size and orientation don't change. The PDFs you pick are not sent to a server; they are processed inside the browser you are using.

When you need to merge PDFs

Portals that accept only one file Job applications, university applications and many online application forms offer a single upload field. Combine the form, the certificates and the portfolio into one PDF in the order the reviewer expects.
Scans split across several files When a scanner or a phone scanning app saves a separate file for every page or every scan, the recipient has to open them one by one. Sort them by name and make one file.
Contracts and their attachments The main text, the appendices and a copy of an ID belong together, and keeping them in one file means no document goes missing.
Sending by email or chat One attachment instead of several keeps the order clear for the recipient. With a personal Gmail account, attachments over 25 MB in total are replaced by a Google Drive link, so check the size of the saved file.
Printing in one go Print a single file with one print command instead of opening each file. If you print double-sided, read the note on odd page counts under "Common mistakes" first.

How to use it

Drop the PDFs on the box at the top, or choose several at once with "Choose PDFs". Files you add later go to the end of the list.
Set the order in the file list. Drag the handle (☰) on the left of a row or use the ↑ ↓ buttons, and for numbered files use "By name" to sort them in one step.
To skip pages, click them in the preview below, or type only the pages you want in that file's pages field (for example 1-3,7). Leave it empty to use the whole file.
Check the large number (pages in the merged document) and the ribbon to confirm that the page count and the order are what you expect.
Type a file name and press "Save PDF". The size of the saved file appears under the large number.

Reading the list, ribbon and preview

File list The files are merged from top to bottom. The row number matches the number in the preview and the ribbon, and the color band at the left of a row matches the colors of the ribbon and the preview bands. The small text under a row shows how many pages are used out of the total, the file size and the number of original bookmarks.
Ribbon The whole merged document drawn as one bar. Each file takes a width in proportion to its pages, so you can see at a glance which file makes up most of the document. Clicking a ribbon segment takes the preview to that file's first page.
Preview Shows the pages in the order they will be merged. The bold number is the page number in the merged document, and the small number beside it is the page number in the original file. The next file starts where the band color changes, and the first page of each file carries its list number.
Hatched pages These are removed pages. Click again to put one back. If a pages field uses an order different from the original (3,1-2) or repeats a page (1,1,5), only the pages that are included are shown, in the order you typed them, and clicking one removes that single occurrence.
Page shape Thumbnails follow the aspect ratio of the original page. If landscape pages or US Letter pages are mixed in, they look different in the preview.

Ways to set the order

Method	Best when	What it does
Drag the handle (☰)	Moving one or two files	Drag a row to where you want it. Works with mouse and touch
↑ ↓ buttons	Moving one step at a time or fixing the order by keyboard	Tab to a button, then each Enter moves the file one place
By name	Numbered files such as scan1, scan2 … scan10	Compares the numbers in names by value, so 2 comes before 10
Name Z-A	Files that start with a date, newest first	The reverse of "By name"
Reverse	Flipping the whole current order	The last file comes first
Adding the same file twice	Inserting another file in the middle of one file	Add A twice, set the pages to 1-3 and 4-, then put B between them

How to write the pages to use

Write pages by their position inside that file (the small number in the preview). Separate parts with commas and write ranges with a hyphen (-). Full-width digits, the tilde (~) and the Japanese comma (、) are accepted too. The examples below assume a 10-page file.

What you type	Pages included
(empty)	All of pages 1 to 10
`3`	Page 3 only
`1-3`	Pages 1, 2, 3
`1-3,7`	Pages 1, 2, 3, 7
`8-`	Pages 8, 9, 10 (from page 8 to the end)
`-2`	Pages 1, 2 (from the start through page 2)
`3,1-2`	Pages 3, 1, 2 in that order (as typed)
`1,1,5`	Pages 1, 1, 5 (the same page twice)

If the first number is larger, as in 5-3, if you type a page the file doesn't have, or if you separate numbers with spaces, the row shows the reason and saving is blocked. This is so that a wrong entry is never merged quietly.

Bookmarks: the original bookmarks under each file name

Bookmarks (the document outline) are the table of contents shown in the side panel of a PDF viewer. They belong to the whole document rather than to a page, so copying pages alone doesn't bring them along. When "Bookmark each file by name" is on, this tool creates one bookmark per file with its name and moves that file's original bookmarks underneath it, keeping their levels. It also keeps the position each original bookmark pointed to (the height on the page and the zoom).

If an original bookmark points to a page you removed, that bookmark is dropped. If it still has lower-level bookmarks, though, its name is kept and it points to the page of its first child.
If you included the same page twice, the bookmark points to the first place it was included.
The merged file is marked to show the bookmarks panel when opened. Whether a viewer follows this setting differs from viewer to viewer.
If you don't need bookmarks, turn the switch off. The original bookmarks are not moved either.

Merging PDFs with form fields

In a PDF with fill-in fields (form fields), such as an application form, the values you typed are stored separately as "fields". Moving the fields as they are can make the values disappear in the merged file, or make field names collide with fields from other files. So this tool draws the form fields of the included pages onto the page exactly as they look now, and fixes them there. Typed text and check marks stay visible and the text is searchable, but you can no longer edit them in the merged file.

If you still have values to change, finish filling in the original, save it, and then merge.
Some PDFs ask the viewer to redraw their fields, so the field look stored in the file can differ from the values on screen; such a file shows a note on its row. Add a copy saved with Print → Save as PDF to keep exactly what is shown.
Fields set to hidden, and fields set not to be shown on screen, are not drawn.
In a PDF with a digital signature, only the look of the signature stays as a picture; the information used to verify the signature is dropped. If a destination needs the original with a live signature, submit the original separately.
XFA forms (some official forms) can't have their page content moved, so they are left out of the merge and their row shows why.

What is kept and what is dropped

Item	Merged file	Reason
Text, fonts, images, shapes	Unchanged	Page content is copied, not redrawn. Image quality is unchanged too
Page size and orientation (rotation)	Unchanged	Each page has its own values, so they travel with the page
Web links, notes, highlights	Kept	They are annotations attached to pages
Form fields	Fixed so the values show	See "Merging PDFs with form fields" above
Bookmarks	Moved under the file name	Not created if you turn the switch off
Layers (optional content)	Kept; layers that were off stay off	The layer settings of the files are combined into one
Links inside a document (from a table of contents to a chapter)	Dropped	Copying a link that points to another page would drag that whole page along
Printed page numbers (i, ii, 1…), document attachments, document scripts, the tag structure for screen readers	Dropped	They belong to the whole document, not to a page
Digital signature verification data	Dropped	A signature covers every byte of the original file, so it can't hold in a new file

If you include the same page twice, its links, notes and highlights stay only where it first appears.

Size of the merged file

Merging joins pages rather than compressing them, so the result is about the size of the originals added together. The 3 samples are 16 KB, 12 KB and 17 KB (45 KB in total), and the merged file is 38 KB. It is a little smaller only because the page lists and document information that each file had are reduced to one set and small items are stored together; no image or font was shrunk.

Even when documents use the same font, the font each file contained stays in the result. The samples work this way too: each of the 3 files has its own font, so the merged file holds 3 copies.
A scanned PDF holds a picture for every page, so it grows with the page count. Using fewer pages makes it smaller accordingly.
If the result is over the limit of where you are sending it (for example 25 MB for a personal Gmail attachment), lower the image quality with PDF compressor after merging, or split it into two files with PDF splitter.

Merging PDFs with different page sizes

A PDF stores a size for each page separately. If you merge an A4 document (210×297 mm) with a US Letter document (8.5×11 in, 215.9×279.4 mm), the result contains both sizes, and this tool doesn't stretch or crop pages. On screen, a Letter page just looks a little wider and shorter. When you print on paper, use "Fit to page" in the print dialog. If the file itself must have one size, export the originals again from their source program on the same paper size and then merge.

Common mistakes

Number order in file names If numbers of different lengths such as 1, 2 and 10 are sorted as text, you get 1, 10, 2. "By name" in this tool compares numbers by value, so you get 1, 2, 10. If the order differs from what another program gave you, this is the reason.
Typing the printed page number In a document where the cover and contents are numbered i, ii and the body starts at 1, body page 1 is the 3rd page of the file. In the pages field, type the small number from the preview (the position inside the file).
Separating numbers with spaces 1 3 could mean pages 1 and 3 or page 13, so it isn't accepted. Write 1,3.
Saving without noticing a missing file A password-protected or damaged file shows the reason on its row and is left out of the merge. If that file's number isn't on the ribbon, it was left out. Remove the password with PDF unlock and add the file again.
The next file starts on the back of a sheet when printing double-sided The file after one with an odd number of pages is printed on the back of the previous file's last sheet. If each file must start on a new sheet, make a one-page blank PDF and put it between them. This tool doesn't insert blank pages automatically.
Editing form fields after merging The form fields in the merged file are fixed and can't be edited. Fix the original and merge again.

Limits and cautions

You can add up to 50 files at a time, 100 MB per file and 300 MB in total, with at most 5,000 pages in one file and 5,000 pages in the merged document. Processing happens in your device's memory, so adding several large files on a phone may freeze the tab. If that happens, merge in two rounds and then merge the two results.
Password-protected PDFs (both those that ask for a password to open and those that only lock editing or printing), XFA forms and files that can't be read are not merged.
The content, size and orientation of pages are not changed. If you need to rotate or delete pages, use PDF page rotator and PDF page deletion alongside it. Convert image files with JPG to PDF before adding them.
Links inside a document, printed page numbers, document attachments, document scripts, the tag structure for screen readers and signature verification data are not carried over.
This tool was tested in Chrome. Processing speed and memory use in other browsers were not measured.

Checked on The standards and help sources and the sample figures were checked on 2026-10-21.

Sources

01ISO 32000-1:2008 Document management — Portable document format (public copy from Adobe)7.7.3.4 inheritance of page attributes, 8.11 optional content (layers) and BaseState, 12.3.3 document outline (bookmarks), 12.5.3 annotation flags (Hidden, NoView), 12.5.5 appearance streams, 12.7 forms, 12.8 digital signatures
02pdf-lib API — PDFDocumentThe functions that copy pages into a new document and save it. This tool builds the file with version 1.17.1 (MIT license)
03pdf.js 3.11.174 — src/display/api.jsgetOutline (bookmarks), getDestination and getPageIndex (the page a bookmark points to). Thumbnails are also drawn with this engine (Apache-2.0 license)
04MDN — Intl.Collator() constructorThe numeric option compares numbers by value ("1" < "2" < "10"). Used for sorting by name
05Gmail Help — Send attachments with your Gmail messageThe attachment limit for personal Gmail accounts is 25 MB; larger files are added as Google Drive links

Frequently asked questions

Are my PDF files uploaded to a server?

No. The PDFs you pick are read and merged inside the browser you are using. Only the tool files needed to open the page are downloaded, and the contents of your PDFs are sent nowhere. The list disappears when you close the page, so save the merged file first.

How many PDFs can I merge?

You can add up to 50 files at a time, 100 MB per file and 300 MB in total, and the merged document can have up to 5,000 pages. Choose several files at once in the file dialog or drop them on the box, and files added later go to the end of the list.

How do I change the merge order?

In the file list, drag the handle on the left of a row or use the ↑ ↓ buttons. For numbered files such as scan1, scan2 … scan10, press "By name" to sort them in one step, comparing numbers by value so 2 comes before 10. "Reverse" flips the current order.

Can I merge only some pages of a file?

Yes. Click the pages you want to drop in the preview below, or type only the pages to use in that file's pages field, such as 1-3,7. Typing 3,1-2 uses them in the order you wrote, and repeating a page as in 1,1,5 includes it twice. Leave the field empty to use the whole file.

What happens to bookmarks (the table of contents) when I merge?

When "Bookmark each file by name" is on, each file gets a bookmark with its name, and the original file's bookmarks are moved under it with their levels kept. Bookmarks that pointed to a page you removed are dropped. Turn the switch off and no bookmarks are added.

Can I merge PDF forms that have fill-in fields?

Yes. The form fields are drawn onto the page with the values you see now, so typed text and check marks stay, but you can't edit them in the merged file. A digital signature keeps only its look, and the verification data is dropped. XFA forms can't be merged.

Why is a password-protected PDF left out?

Files that ask for a password to open, and files that only lock editing or printing, have their content protected by the password, so moving their pages without unlocking would produce a broken file. The row shows the reason and the file is left out of the merge. If you know the password, unlock it with PDF unlock and add it again.

Does merging make the file smaller?

Hardly. Merging joins pages rather than compressing them, so the result is about the sum of the originals. The three samples total 45 KB and the merged file is 38 KB, smaller only by the document information each file had. To shrink it further, use PDF compressor after merging.