How many PDFs can I merge at once?

Between 2 and 10 files in a single merge.

Is there a page limit?

Yes. The combined total is up to 80 pages.

Can I change the order of the files?

Yes. Move files up or down in the list before merging.

Can I merge only certain pages?

Not directly. Extract the pages with the PDF Splitter first, then merge those files.

Does merging reduce quality?

No. Pages are copied, not re-rendered, so text and images look the same.

Can I add JPG or PNG files?

No, only PDFs. Convert images with the Image to PDF tool first.

Are my files uploaded?

No. Merging happens entirely in your browser.

Can I merge files that use different page sizes?

Yes—pages keep their own sizes unless you later normalize them in an editor.

How do I insert a cover PDF at the front?

Place the cover file first in the merge order before combining.

Will bookmarks from each file survive?

Some mergers preserve bookmarks; verify in a viewer if navigation matters.

Can I merge scanned and text PDFs together?

Yes—output contains both page types; OCR remains only where it already existed.

What if one file is already a portfolio?

Flatten or extract portfolio documents first so merge sees ordinary pages.

Does merging re-compress images?

Usually pages are copied; size drops more from removing dupes than from new compression.

How should I name the merged download?

Include project and date so teammates can tell versions apart.

Can I undo a bad page order after merging?

Split or rearrange with a PDF organizer, or rematch from the original files.

Are form fields still fillable after a merge?

AcroForm fields may remain, but name collisions can break scripts—test interactive files.

Is there a privacy risk merging confidential decks?

Work locally and avoid uploading sensitive PDFs to third-party services when policy forbids it.

Image Tools

How to Merge PDF Files Into One Document

By Tools Star Hub Editorial Team · Published November 4, 2026

Quick answer: open the PDF Merger, add between 2 and 10 PDF files, arrange them in the order you want, and press merge. The pages of each file are copied, one file after another, into a single merged.pdf that you download. Each file can be up to 20 MB, the combined total can be up to 80 pages, and the whole job runs in your browser.

Applications, reports and contracts often arrive as several separate PDFs, while the person receiving them wants one file. Merging puts a cover letter, a form and its attachments into a single document that is easier to send, review and archive.

How does merging PDFs work?

The merger opens each PDF you add, copies all of its pages in their existing order, and appends them to a new document. The pages themselves are not re-rendered or converted to images, so text stays selectable and the quality is the same as in the originals.

The order of the files in the list decides the order in the final document. File one's pages come first, then file two's, and so on.

How to Merge PDF Files: Order, Limits and Privacy — Tools Star Hub

What are the limits for merging?

Limits keep the tool fast and reliable in a browser tab, especially on phones.

PDF Merger limits
Limit	Value
Number of files	2 to 10
Size of each file	Up to 20 MB
Total pages across all files	Up to 80
Password-protected PDFs	Not supported
Output	One file named merged.pdf

If you have more than 80 pages in total, merge in two rounds: combine the first group, then merge that result with the rest, keeping each round under the page limit. You can check page counts beforehand with the PDF Page Counter.

How do I put the files in the right order?

After adding files, use the move up and move down controls in the list. Think of the final document from the first page: a cover letter or summary usually goes first, followed by the main document and then appendices.

If you need to change the order of pages within a single file, or drop a few pages, use the PDF Splitter first to extract exactly the pages you want, then merge the results.

Can I merge password-protected PDFs?

No. Encrypted PDFs cannot be opened to copy their pages, so the tool rejects them with a message. If the file is yours, open it in a PDF reader that knows the password and save or print an unprotected copy, then add that copy.

Only remove protection from documents you are allowed to change. Some files are locked deliberately by their sender.

What if some of my documents are photos?

The merger accepts PDFs only. Convert JPG or PNG photos and scans to PDF first with the Image to PDF tool, then add that PDF to the merge list alongside your other documents.

Will the merged PDF be large?

Roughly, the merged file is about the size of the inputs added together, because pages are copied rather than recompressed. Scanned documents with large page images make big files. If the result is too large to email or upload, run it through the PDF Compressor.

When is merging PDFs most useful?

Job and visa applications often ask for a single upload containing several documents. Accountants receive a month of invoices that are easier to review as one file. Teachers combine worksheets, and teams join chapters written by different people into one report.

In each case, the merger keeps every page as it was, so signatures, stamps and layouts look exactly as in the originals.

Are my PDFs uploaded to a server?

No. Files are read and merged inside your browser tab and the result is saved straight to your device. That is important for contracts, medical letters and financial statements that should not leave your computer.

What is kept from the original PDFs?

The visible content of every page is kept exactly: text, images, vector graphics, page size and orientation. A merged document can therefore mix A4 and Letter pages, or portrait and landscape pages, just as the originals did.

Document-level extras that belong to a whole file rather than to a page, such as the outline of bookmarks shown in a reader's sidebar, are generally not carried across when pages are copied into a new document. If your readers rely on bookmarks, add them again in a desktop PDF editor after merging.

How should I name and check the merged file?

The download is always called merged.pdf, so rename it to something your recipient will recognise, such as the applicant's name and the document type. A clear name helps when the file ends up in a folder with many others.

Before sending, open the file and check the page count. It should equal the page counts of the inputs added together. The PDF Page Counter gives you a quick total if the document is long.

Can I merge PDFs on a phone?

Yes. The tool runs in mobile browsers as well as on a computer. On a phone, pick the files from your downloads or files app, arrange them, and save the merged file back to the same place. The page and size limits keep the job light enough for most phones to handle without running out of memory.

Very large scanned PDFs take more memory, so if a merge fails on an older phone, try fewer files at a time or compress the inputs first.

What if a file will not merge?

A clear message tells you which file caused the problem. Password protection is the most common reason. A damaged or incomplete download is the next most likely, and downloading the file again usually fixes it. If a file is not really a PDF, for example a Word document renamed to end in .pdf, convert it properly with the Word to PDF tool first.

How do I plan a merge with many documents?

Start by listing the documents in the order the reader expects. Check each file opens, note its page count, and add up the total. If it is over 80 pages or more than 10 files, group them into batches that each fit the limits, merge each batch, and then merge the batch results.

Remove pages you do not need before merging rather than after. Splitting out only the relevant pages keeps the final document shorter and easier to read, and it keeps you comfortably inside the page limit.

Does merging change text or links inside pages?

No. Because each page is copied rather than redrawn, selectable text stays selectable and searchable in the merged file, and the layout of every page is identical to its source. Forms and signatures that were already flattened into the page look the same as before.