# Merge PDF Files Online for Free

> A free online tool that joins two or more PDF files into one PDF in the order you set, copying the pages as they are with the qpdf command-line program.

Merge PDF files in one step with this free online tool. Add two or more PDFs, put them in the order you want, and download one merged.pdf. No signup is needed for a small job, and the pages stay as they were in the source files.

## Key facts

- Input: 2 to 5 PDF files without an account (20 signed in), up to 10 MB per file and 20 MB together (50 MB and 100 MB signed in), up to 100 pages in all (500 signed in); the type is read from the file content.
- Output: one PDF with the files in the order of your list; pages are copied without re-encoding. In our test three generated PDFs of 2, 1 and 3 pages (46, 42 and 48 KB) became one PDF of 6 pages and 124 KB in that order.
- Encrypted PDFs (password or permission restrictions) are refused and are never opened or broken; a slightly damaged PDF is repaired automatically and the result panel says so, unless repair is turned off.
- Without an account each file is uploaded with its own human check. Bookmarks, links and form fields of the source files were not tested.
- API: POST each PDF to https://api.aiipworld.com/v1/uploads, then POST https://api.aiipworld.com/v1/pdf-jobs with op pdf_merge and the upload ids in merge order, and poll GET /v1/jobs/:id.
- Free without an account: 20 PDF jobs per day per visitor, no watermark. Signed in, each job costs 1 credit plus 1 credit for each started 20 MB of result beyond the first 20 MB (100 free credits every month).
- Files are deleted automatically: 10 minutes after conversion without an account, 1 day with a free account.

## How it works

1. Choose or drop at least 2 PDF files into the upload box. Signed-in users can add up to 20 files.
2. Check the list. Drag a file, or use the up and down arrows, to set the order.
3. Remove any file you do not need with the X.
4. Click "Merge PDF" and wait for the result panel.
5. Check the preview and page count, then click Download PDF to save merged.pdf.

## How to merge PDF files

Add your files, set the order, and run the job. The tool joins the files into one PDF and shows the result in the panel below. Each file must be a real PDF, so check the file type before you start if a file will not load. The steps are the same for a two-file job or a longer one. Start with the file that should come first, because the first file in the list becomes the first pages of the result.

## What this PDF merger does

This tool joins two or more PDF files into one PDF. It does not edit the text of your pages, and it does not add a watermark. The result panel shows the page count, the size, and the credits reserved, and it says when a file had to be repaired. The merge is done by qpdf, a command-line PDF program that runs on our server as a separate process.

## Combine PDFs into one document

This PDF combiner joins files into one document, so merging and combining mean the same thing here. To combine PDFs, add the files, set their order, and click "Merge PDF". You can merge PDF documents that have different page counts, as long as each file is a real PDF that is not encrypted. If you searched for "mergepdf" as one word, this is the same tool.

## Put the files in the right order

The order of the list is the order of the pages in the result. Drag a file, or use the up and down arrows, to move it. The first file in the list comes first in merged.pdf. Check the list before you click "Merge PDF". Remove a file with the X if it was added by mistake. If you add the same file twice, it is uploaded twice and its pages appear twice.

## Combine PDF files without changing the pages

Merging copies the pages as they are. Nothing is re-encoded, so text, fonts and images in the pages keep their quality. This is how the merge works, and it is the reason the result should look like the source pages. In our test we merged three generated PDFs: a 2 page report of 46 KB, a 1 page invoice of 42 KB, and a 3 page appendix of 48 KB. The result was one PDF of 6 pages, 124 KB, with the pages in the order of the list. This was a generated test, not a real document, so your results may vary.

## Limits: files, size and pages

Limits depend on whether you are signed in. Without an account you can merge 2 to 5 files, with up to 10 MB per file and 20 MB together. Pages are counted across all files, up to 100 pages. Signed in, you can merge up to 20 files, up to 50 MB per file and 100 MB together, with up to 500 pages. The web tool gives a signed-in job 60 seconds and an anonymous job 30 seconds. Each merge uses 1 credit, plus 1 credit for each started 20 MB of the result beyond the first 20 MB.

- The web tool handles one job at a time.
- Free web tool: 20 jobs per day per visitor.

## Why each file needs its own human check without an account

Without an account, each file is uploaded with its own human check. This check is Cloudflare Turnstile, and it helps keep the free tool available. Signed-in users skip the check and use credits instead. Because of this, the upload may pause for a moment between files. An upload counts toward 40 uploads per day per visitor. If you plan to merge many files, signing in will make the process smoother.

## Encrypted, damaged and disguised files

Encrypted PDFs are refused. This includes PDFs with a password to open them and PDFs with permission restrictions, of any strength. No password is accepted, and no attempt is made to open or break the protection. Remove the protection in the program that made the file, then upload it again. A damaged PDF is repaired automatically when possible, and the result panel says so with "The file had minor damage that was repaired automatically". A file that cannot be repaired is refused. The setting "Repair a slightly damaged PDF automatically" is on by default; with it off, a damaged file is refused. File type is read from the first bytes of the file, not from its name. A renamed file is treated as what it really is, so a file that is not a PDF will be refused even if it has a .pdf name.

## Merge only some pages

Merge does not take page ranges. It always joins whole files. To merge only some pages, first use the Split PDF tool's "pick pages into one PDF" on each file, then merge the results. The Split PDF tool is at /tools/split-pdf/. This two-step method lets you pick the pages you need from each file. Check the page numbers in the split result before you merge it.

## What to check in the merged file

Check the page count in the result panel. The pages in should match the total of the files you added, and the pages out should match the number you expect. The result is checked after writing, so the page count must match what was expected. Open merged.pdf and look at the first page of each source file. Check the order and the content. Bookmarks, links, form fields, tags and metadata of the source PDFs have not been tested. If your PDFs have them, check the result before you share it.

## Merge PDF files from code

You can merge PDFs from your own code with the PDF jobs API. First, POST each PDF to https://api.aiipworld.com/v1/uploads as raw bytes with Content-Type application/pdf. The answer has an upload_id for each file. Upload one file per request. Then POST a JSON body with op, params and files to https://api.aiipworld.com/v1/pdf-jobs. Use op pdf_merge with the upload IDs in merge order, from 2 to 20 files. Send your API key with Authorization: Bearer or x-api-key. Then poll GET /v1/jobs/:id until the job succeeds or fails. The page shows a ready cURL, Node and Python example below the tool, built from the settings you chose. Common errors include 400 invalid_params, 413 file_too_large, 422 not_a_pdf, 404 upload_not_found, 402 insufficient_credits and 429 rate limited. A failed job can return error_code values such as encrypted_pdf or corrupt_pdf. See /docs/ for the general API.

## Privacy: what happens to your files

Your uploaded files are sent to our server. Nothing is processed in the browser. The uploaded file is used only to make the result. The working copy of the upload is deleted as soon as the job ends, whether it succeeds or fails. The result is deleted after 10 minutes in the free web tool, and no history is kept. Download links are short-lived, so save merged.pdf when the result panel shows it. You must have the right to use the files you upload, as set out in our Acceptable Use Policy.

## Questions

### Can I merge PDF files for free?

Yes, you can merge PDF files for free in the web tool, with no signup needed for a small job. Each file is uploaded with its own human check.

### How to combine PDFs into one file?

Add two or more PDF files, set their order, and click "Merge PDF". The tool combines them into one merged.pdf that you download. Without an account you can combine 2 to 5 files.

### How many PDF files can I merge at once?

Without an account you can merge 2 to 5 files at once. Signed in, you can merge up to 20 files.

### Can I change the order of the files?

Yes. Drag a file, or use the up and down arrows, to change the order. The first file in the list comes first in the result.

### Does merging reduce the quality?

No, merging does not re-encode the pages. Text, fonts and images keep their quality. Results can vary by file, so check the merged PDF.

### Can I combine PDF files that have a password?

No. Encrypted PDFs are refused, including password-protected files and files with permission restrictions. No password is accepted, so remove the protection in the program that made the file first.

### What happens to a damaged PDF?

A damaged PDF is repaired automatically when possible, and the result panel says so. A file that cannot be repaired is refused. You can turn off automatic repair, and then a damaged file is refused.

### Can I merge only some pages of a PDF?

Yes, but not directly. Merge takes whole files. Use the Split PDF tool's "pick pages into one PDF" on each file first, then merge the results.

### Why do I have to complete the human check for each file?

Without an account, each file is uploaded with its own human check, which uses Cloudflare Turnstile. Signed-in users skip the check and use credits instead.

### How big can the merged PDF be?

The result can be up to 200 MB. Signed in, each input file can be up to 50 MB, and all files together up to 100 MB.

### Are my files kept?

Your upload's working copy is deleted as soon as the job ends. The result is deleted after 10 minutes in the free web tool, and no history is kept.

### Can I merge PDFs in my own code?

Yes, you can merge PDFs from code. Upload each PDF to /v1/uploads, then send a pdf_merge job to /v1/pdf-jobs with the upload IDs in order. See /docs/ for the general API.

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Page: https://aiipworld.com/tools/merge-pdf/