Merge PDF files — combine documents in your browser
Drop multiple PDF files below, reorder them as needed, and merge them into a single document in one click. Everything runs in your browser via pdf-lib — your files never leave your device.
Your file is processed entirely in your browser. Nothing is uploaded.
Merging PDFs is one of the most common document operations in the world. A contract arrives as five separately-signed pages. A report is built from a cover, a body, and an appendix each saved as their own file. Scanned receipts pile up as individual PDFs that need to become one expense report. Tax forms come from different portals and need to be combined before filing. Every one of these workflows ends with someone searching for a way to merge PDFs — and most of the tools that show up require uploading your files to a third-party server, which is a deal-breaker for confidential content.
This tool runs entirely in your browser. It uses pdf-lib, a pure-JavaScript library, to open each PDF you add, copy its pages into a new document in the order you choose, and save the merged result as a single PDF you can download immediately. No file ever leaves your device. There is no server, no upload, no log, and no account required. You can disconnect from the internet once the page has loaded and the tool keeps working. Add your files, drag to reorder, click merge, and download.
How to merge PDF files in 4 steps
- 1
Add your PDF files
Drop multiple PDFs into the dropzone at once, or click to browse and select several. You can also add more files afterward.
- 2
Reorder if needed
Use the up and down arrows next to each file to change the order. The merged output will follow this exact sequence.
- 3
Click Merge PDFs
pdf-lib opens each PDF, copies every page in order, and assembles them into a single document. Most merges finish in under a second.
- 4
Download the merged PDF
Save the combined PDF to your device. Every page from every source file is there, in the order you chose.
Why merge PDFs instead of emailing separately?
Sending five separate PDF attachments is messy for the recipient. They have to open each one, guess the correct order, and keep track of which file belongs where. A single merged PDF is one file, one download, one print job, one archive entry. It is also the format most portals and systems expect — a job application wants one PDF with the resume, cover letter, and references combined; a tax filing wants all forms in one document; an invoice submission wants the cover sheet and the receipts bundled together. Merging is the simple act of taking N separate documents and producing one coherent whole, and doing it in the browser means you never have to trust a third-party server with your content.
When should you merge PDFs?
Combining a resume, cover letter, and references
Most job portals accept only a single PDF upload. Merging your separate documents gives the recruiter everything in one polished file.
Assembling scanned receipts for an expense report
Individual receipt scans need to become one PDF before your accounting system will accept them. Merge them in order, submit, done.
Bundling contract pages signed separately
Different signatories often sign different pages. Merging the individually-signed PDFs produces one complete, legally-coherent contract.
Combining tax forms from multiple sources
W-2s, 1099s, and other forms arrive as separate PDFs from different portals. Merging them into one document makes filing faster and reduces the risk of losing a form.
Frequently asked questions
- How many files can I merge?
- There is no hard limit. The tool merges as many files as your device’s memory can handle. In practice, combining 50+ files and 500+ pages works fine on a modern laptop. Mobile devices may struggle above 200 pages due to stricter memory limits.
- Does the merge preserve bookmarks and links?
- pdf-lib copies the page content faithfully (text, images, vectors, annotations). Internal bookmarks (the outline panel) and cross-document hyperlinks may not carry over in all cases because they reference page indices that change during the merge. For simple documents this is rarely an issue.
- Can I merge password-protected PDFs?
- The tool attempts to open each PDF with ignoreEncryption mode. This works for PDFs that have an empty owner password (most read-only-restricted PDFs). Fully encrypted PDFs that require a user password to open will fail — remove the password in Acrobat first.
- Does the order of files matter?
- Yes. Pages are added in the exact order shown in the file list. Use the up and down arrows to reorder before merging. The first file’s pages come first in the merged output, then the second file’s pages, and so on.
- Are my files uploaded to a server?
- No. The entire merge operation runs inside your browser through pdf-lib. Each PDF is read locally, pages are copied locally, and the merged output is produced locally. FileShrink has no server that touches your files. You can verify by running the tool with your network disconnected.