1. Tool Introduction
The PDF online merge tool allows you to combine multiple PDF files into one single document in your preferred order.Common usage scenarios:
- Merge separate PDF contracts and invoices into one file for easy archiving and filing.
- Combine split chapters of PDF e-books into a complete full version.
- Put multiple scanned files together to form a complete formal report.
2. Operation Steps
Step 1: Select PDF Files
Click the Select File button, or drag and drop PDF files directly into the upload box. You can select multiple PDFs at one time by holding the Ctrl or Cmd key.
After uploading files, the tool will automatically:
- Display file name and file size in KB/MB
- Analyze and show the total pages of each PDF; prompt an error if the file is encrypted or damaged
- Show the estimated total pages after merging at the bottom of the list.
Note: Password-protected PDFs are not supported directly. If your PDF is encrypted, the tool will prompt Encrypted, please remove password first. Please use our PDF Password Remover tool to decrypt before merging.
Step 2: Adjust Merge Order by Drag and Drop
Every file card in the list can be dragged up and down freely. Files will be merged in top-to-bottom order as shown in the list.
- Click and hold anywhere on the card, then drag up or down to adjust position.
- The list order updates immediately after dragging.
- Click the Remove button on each card to delete unwanted files separately.
Step 3: Start Merging
- Make sure you have selected at least 2 valid PDF files and confirmed the order.
- Click Start Merge button.
- The tool will load files one by one and combine them into a new complete PDF.
Step 4: Download Result
- Once merging is finished, the browser will pop up the download link automatically.
- Click Download merged.pdf to save the merged file to your device.
3. Feature Highlights
表格
FeatureDescriptionAutomatic Page DetectionInstantly read page count of each PDF after selection, no manual input needed.Drag & Drop SortingAdjust merge order visually without reselecting files.Total Page PreviewShow total pages in real time to help you know the full document length.Encryption DetectionClearly remind encrypted PDFs to avoid merge failure.Single File RemovalDelete any single file anytime without clearing all selections.100% Local ProcessingAll tasks run inside your browser, files never leave your device.
4. Notes
- Encrypted PDF: This tool cannot process password-locked PDFs. Please decrypt first with our PDF Password Remover.
- File size limit: Single PDF better under 100MB, total pages recommended within 1000 to avoid high browser memory usage.
- Order confirmation: Double-check the file order before merging; the process cannot be undone after completion.
- File name: The downloaded file is named merged.pdf by default, you can rename it manually after saving.
5. FAQ
Q1: Can I merge PDFs with different page sizes, such as A4 and A3?A: Yes. All pages keep their original size and will be joined directly without automatic scaling.
Q2: Will the merged PDF lose image or text quality?A: No. This tool uses the pdf-lib library to copy pages losslessly. All text, vector graphics and original clarity are fully preserved.
Q3: How to change the merge order?A: Simply drag the file card up or down. You can also remove and re-add files, but drag-and-drop is much easier.
Q4: Why does a file show parse failed?A: The file may be encrypted, corrupted, or not a standard PDF. Please check if the file is intact and password-free.
Q5: Is there a limit on how many PDFs I can merge at once?A: There is no fixed limit, but restricted by browser memory. We recommend merging no more than 20 files in one task.
