Merged PDF not right? Find the problem and fix it

What you see, and where to look

Merging copies every page exactly as it is, so a wrong result almost always comes from the cards you started with, or from the files themselves. Merge PDF keeps your cards on the page after merging, so you can change them and merge again. Find your problem:

A file didn't go in, or the button won't work

Every file you add becomes a card, with its first page, its name, its page count and its size. A card with a warning has no number in its corner, and it is left out of the merge. The button counts only the usable cards, so it can say Add one more PDF to merge when you have added two files and one has a warning. Read the warning on the card:

"Locked with a password."

The file needs a password to open. Remove the password from a copy with Unlock PDF, which needs the password, then add that copy. Remove the locked card with its × button.

"This file can't be read as a PDF. It may be damaged."

It may not have downloaded fully. Download it again, or ask the sender for a new copy.

"Only PDF files work here."

Photos and Word files can't be merged as they are. Turn photos into a PDF with JPG to PDF, and save Word files as PDF from Word, or with Word to PDF.

"No preview."

The browser couldn't draw the first page, but the file is still merged. Check it in the result.

The easiest check afterwards is to add up the pages. If your cards say 2, 3 and 1 pages, the result should say 6 pages. If it says fewer, a card was left out. The post Merge or compress a password-protected PDF has the whole routine for locked files.

The pages are in the wrong order

The pages of card 1 come first, then those of card 2, and so on. Inside each file, the pages keep their own order. New files go to the end. If the result is wrong, your cards are still there, so drag them into place and press Merge again. The Merge button comes back whenever you move, add or remove a file, so the PDF you download always matches the cards.

• On a computer, drag a card from anywhere. On a phone, drag it by the numbered handle in its top-left corner. Touching the rest of the card scrolls the page as usual.
• Number your files before you add them, like 1-cover-letter.pdf and 2-resume.pdf. Many devices list files by name, so they arrive in order. Use two digits (01, 02, ... 10) if you have more than nine.
• Tell similar files apart by their first page. Two marksheets with almost the same name are easy to swap, and the first page on the card shows which is which.
• The pages inside one file are in the wrong order? Merge keeps each file's pages together. To move single pages, or pages between files, use Organize PDF. The post Rearrange pages in a PDF shows how.

For a job or college application, Combine resume, cover letter and certificates in one PDF suggests the order portals usually expect. The form's own notice always wins.

Pages of different sizes, or sideways

Different sizes in one file

Each page keeps its own size, crop and rotation. An A4 page stays A4 and a landscape page stays landscape, even next to a Letter page from another file. That keeps every page exactly as it was, but a file made from a scan, a downloaded form and a photo can mix sizes. It reads fine on screen. When printing, choose Fit to page (or Fit to printable area) in the print window, which scales each page to the paper. Look at the preview first.

To make every page A4, use Resize PDF on the merged file. It is built for exact sizes, and also changes the page size to A4. The post Change PDF page size to A4 has the steps, and A4 vs Letter explains the difference between the two.

Sideways or upside-down pages

A page that was scanned sideways stays sideways, because each page keeps its own rotation. Turn it upright with Rotate PDF, before or after merging. If only a few pages are turned, Rotate specific pages in a PDF shows how to turn just those.

Blank or extra pages

Scanner apps sometimes save blank backs of one-sided papers. Merge copies them too. Take them out afterwards with Organize PDF's delete button, or see Delete pages from a PDF. Removing blank pages also makes the file smaller.

The merged file is too big

A merged PDF is about as big as your files added together. Merging doesn't compress anything: every page is copied with its pictures and fonts, so nothing gets blurry, but the file doesn't get smaller either. In our tests, three scans of 14 pages in all, 23.1 MB together, merged into a 23.1 MB file in 0.3 seconds. Typed pages are small; scans and photos are what make PDFs big.

To bring a merged file under a limit:

1. Leave out pages nobody needs, such as blank backs or a cover page. All pages share one limit, so each page you remove gives the rest more room.
2. Merge first, then make it smaller. Put the merged PDF through the PDF compressor. Shrinking the one file, not each part, means you don't have to guess how much room each part may take.
3. For an exact number, use Resize PDF, which makes the sharpest version that fits, such as 200 KB or 100 KB.

Do it in that order. If you shrink each file and then merge, the sizes add up again: two 190 KB files joined make a file of about 380 KB. Merge PDFs into one file under 200 KB walks through a worked example.

Bookmarks, titles and form fields look odd

A PDF holds more than its pages. A few parts follow their own merge rules, which can look odd until you know them:

Bookmarks aren't what I expected.

You choose when you merge. One per file (the default) gives a bookmark named after each file, holding that file's own bookmarks. Keep theirs keeps the files' own bookmarks, one file after another. None leaves the merged PDF without bookmarks. Change the choice and press Merge again.

The document title shows my cover letter's title.

The merged PDF takes its title, author, attached files and scripts from the first file. Put the file whose title you want first, or rename the merged file.

My page labels (i, ii, iii) are gone.

Page labels are left out, so the pages are numbered 1, 2, 3 from the start. Numbers printed on the page itself stay. Read Why the PDF says page 3 when the page says 1.

A form's second copy has fields called Name_2.

That's on purpose. When a later file uses a field name an earlier file already has, it is renamed, so each copy keeps its own answers. All 16 fields of two merged copies of one form stayed fillable in our test.

Page numbers aren't continuous.

Each file's own numbers stay as printed. Merge first, then add numbers to the finished file with Add Page Numbers, so they run through the whole document.

Passwords, signatures and memory

• Editing restrictions. A PDF that opens without a password but doesn't allow changes can be merged, and the merged PDF opens without those restrictions. The result says so.
• A digital signature. A signed PDF, such as an e-signed agreement, can be merged, but the merged copy no longer carries a valid signature, since the signature covers only the file as it was signed. The result says so. If someone must check the signature, send the original too.
• "These files are too big to handle in this browser's memory." Close other tabs, merge in two rounds (half the files, then that result with the rest), or use a computer. Merging the 455 MB scan took the browser about 1.9 GB more memory than when idle, because the files and the new PDF are held in memory while it is made.
• The merged file has a different name than expected. It is named after your first file: resume.pdf first gives resume-merged.pdf. Your own files are not changed.

A two-minute check before you send it

1. Look at the page count in the result. Does it equal the pages on all the cards?
2. Open the file and flip through first, middle and last pages of each part. Are they upright and in order?
3. Open the bookmarks panel. Does each bookmark go to the right page?
4. Look at the size. Is it under the limit? If not, shrink it last.
5. Give it a clear name, like Priya-Sharma-application.pdf, and keep your separate files in case one part changes.

Merge again as often as you like

Merge PDF has no upload step, so trying again costs no waiting and shares nothing. Your files are never sent anywhere: your own browser builds the new PDF. The page contacts only this site and Google's ad service, which shows the ads that keep the tools free, and our code never gives your files to the ad code. The privacy policy has the details.