Privacy First
Uploaded files are automatically and permanently deleted within two hours.
Automatic deletion
Merge PDF
Combine several PDF files into one document – drop the files, arrange the order, merge. No account, no watermark.
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Free: Merge up to 20 PDFs per run with no sign-up and no watermark.
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Your order: Arrange the files in the dialog before merging; pages keep their original quality.
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Privacy: Uploads are deleted after 30 minutes, the merged PDF after 2 hours.
Combine PDF files
Merge PDFs in the order you want
Select two or more PDFs, put them in order in the dialog and download one combined file. The merge is done with qpdf, which copies the pages of each document exactly as they are – fonts, images and vector graphics are not re-encoded, so the result has the same quality as the originals.
How to use Converter App
1
Add your PDFs
Select several files at once, drop them into the box or import them from Google Drive. Up to 20 PDFs per merge.
2
Arrange the order
The dialog lists the files in the order they will appear. Move files up or down, remove one or add more before you confirm.
3
Download the merged PDF
One file with all pages, ready in a few seconds. Save it to your device or push it to Google Drive.
Key features
Lossless
Pages are copied as PDF objects; nothing is rasterised or recompressed. A 300 dpi scan stays a 300 dpi scan.
Any page sizes
A4 and Letter, portrait and landscape, single and multi-page files can be combined in one document; every page keeps its own size and orientation.
Up to 20 files
Merge up to 20 PDFs in one go. Need more? Merge in batches and combine the results again.
Clear error messages
Password-protected or damaged files are reported by name before anything is merged, so you know exactly which file to fix.
Experience & privacy
Built for reliable document conversion.
Backed by 10+ years of engineering expertise in large-scale data and scientific computing, it’s built for real-world document workflows that require accurate layout preservation, strict privacy, and dependable, high-level performance.
Trusted by Users
Rated 5 stars on Trustpilot for speed, reliability, and ease of use.
User trust
Academic Use
Referenced in published research and used for interview transcription and qualitative data analysis.
Research use
How the PDF merger works
A PDF is a container of page objects that reference shared resources such as fonts and images. Merging means creating a new container and copying the page objects of every input in the chosen order. Converter App does this with qpdf, an open-source library used in many PDF tools, via its page-selection feature: every page is transferred byte for byte together with the resources it needs. Because nothing is rendered or recompressed, the merged file has exactly the quality of its parts, and the operation finishes in seconds even for long documents.
Typical uses
- Combine a cover letter, CV and certificates into one application PDF.
- Join scanned pages or chapters that a scanner saved as separate files.
- Collect invoices or receipts of a month into one document for bookkeeping.
- Put a signed contract and its annexes into a single file before sending it.
Tips before merging
- Name the files so that the intended order is obvious, or arrange them in the dialog – the list shows exactly what the result will look like.
- Unlock password-protected PDFs first; encrypted inputs are rejected by name.
- Mixed page sizes are fine, but if you want a uniform look, print the odd document to A4 or Letter before merging.
- If the merged file is too large to send, run it through the Compress PDF tool afterwards.
Privacy and limits
No account, no watermark, up to 20 files per merge. Uploads are removed after 30 minutes and results after 2 hours; nobody looks at the documents. The tool runs on infrastructure operated by Converter App and is free to use within fair use.
FAQ
Frequently Asked Questions
How many PDFs can I merge, and is there a size limit?
Up to 20 PDF files per merge, with no fixed limit on pages or megabytes within fair use. Large scans simply take longer to upload. If you have more than 20 files, merge them in groups and then merge the resulting PDFs once more – nothing is lost in the second pass.
Can I change the order of the files?
Yes. After selecting the files a dialog shows the merge order with arrows to move each file up or down and a button to remove it. The pages of the first file come first, then the pages of the second file and so on. Pages inside a file keep their order; to reorder individual pages use the PDF Editor instead.
Does merging reduce the quality or change the pages?
No. Merging copies the existing page objects into a new file; images, fonts and vector graphics are not re-encoded. Page sizes and orientations are preserved individually. Bookmarks, form fields and annotations are kept where possible, but bookmarks from several files are not combined into one outline.
Why is one of my files rejected?
Two reasons are common. A PDF that asks for a password when opened must be unlocked first with the Unlock PDF tool. A file that is not really a PDF (for example a renamed image or a damaged download) cannot be read; open it in a viewer to check, and re-export it as PDF if needed. The error message names the file so you can fix just that one.
Can I merge PDFs from Google Drive?
Yes. Use the Google Drive button in the upload box to pick a file; it is added to the merge list like a local upload, and you can mix Drive files with local files. After merging you can push the combined PDF back to your Drive from the result page.
What happens to my files?
Files are transferred over HTTPS and merged on our own servers. Uploads are deleted automatically 30 minutes after the upload, and the merged PDF 2 hours after it was created. No account or email address is required.