Merge PDF
Combine multiple PDF files into a single document
Updated · Guide: How to Merge PDF Files: Complete Guide
Runs in your browser. Your file is processed on this device and never uploaded.
Drop PDF files here
Add multiple PDFs to merge
Max 50 MB
Add PDFs to start
Up to 50 MB per file
No daily limit and no watermark on the result.
No account needed
Free to use. No signup, no email, no trial.
How to use Merge PDF
Upload your PDF files
Click the upload area or drag and drop your PDF files. You can select multiple files at once.
Arrange the order
Drag the file thumbnails to reorder them, or remove any file you don't need.
Click Merge PDF
The files are combined in your browser. No data is sent to a server.
Download the merged PDF
Click the Download button to save the combined PDF to your device.
What is PDF merging?
Combine multiple PDF files into a single document in seconds. Drag and drop your files, arrange them in order, and download the merged result. See our processing model for details on how this tool handles your files.
Merging PDFs combines several PDF files into one document, page for page, in the order you choose. A typical case: two signed pages, a cover letter, and a scanned appendix arrive as three separate files, and the recipient wants one document. Merge PDF joins them in seconds, with nothing to install and no account to create.
Merging happens client-side using PDF-lib (see our processing model for details), and the output is a standard, fully compatible PDF that opens in any PDF reader.
Page content travels across unchanged. Embedded font subsets, annotations and comments, vector artwork, and scanned page images are copied as page objects rather than re-rendered. That is also why merging a 40 MB scan takes roughly as long as merging a 40 KB invoice: the operation is bookkeeping over object references, not rasterisation. Two things are not rebuilt: document-level bookmarks (the outline) and the interactive form dictionary. Form fields keep their visible values, but they may stop being fillable in the merged file, so fill in and save forms before merging.
For best results, ensure all source PDFs use the same page orientation. If some pages are sideways, use the Rotate PDF tool first. After merging, you can add page numbers to create a professionally formatted document, or compress the result if the combined file exceeds email attachment limits. Since each input file must be under 50 MB individually, very large documents can be merged in batches if needed.
Frequently asked questions
Is it safe to merge PDFs online?
Yes. The merge happens locally using PDF-lib in your browser tab, so your documents stay on your device. See our processing model for full details on how Utilavo handles files.
How many PDFs can I merge at once?
You can merge as many PDFs as you like. Each file must be under 50 MB, and the total size of all files should be manageable for your browser. Very large sets of high-resolution PDFs may require more time to process.
Will merging PDFs reduce their quality?
No. The merge operation preserves all content exactly as-is: text, images, vector graphics, and annotations are all retained at full quality. The tool does not re-render or compress any content during merging.
Can I merge password-protected PDFs?
Password-protected PDFs must be unlocked before merging. You can use the Unlock PDF tool on this site to remove the password first, then merge the resulting files.
Can I merge PDFs with different page sizes?
Yes. PDFs with mixed page sizes (for example Letter and A4, or portrait and landscape) merge without any issues. Each page retains its original dimensions in the combined output. If you need uniform page sizes, consider printing each source to a standard size before merging.
Are bookmarks kept when I merge PDFs?
Bookmarks are not carried over. The merge copies pages, while bookmarks (the outline) live in a separate document-level structure that points into the original files. If navigation matters, re-create the bookmarks in a desktop PDF editor after merging, or add page numbers so readers can reference sections.
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