PDF Merge Tool

PDF merging combines multiple separate PDF documents into a single file by copying pages from each source document in sequence. This tool uses the pdf-lib JavaScript library to perform all operations directly in your browser, ensuring complete privacy since files never leave your device.



When you upload PDFs, the tool reads each file as a binary array buffer, loads it into memory using pdf-lib's PDF parser, then creates a new blank PDF document. It iterates through your selected PDFs in order, copying all pages from each document and appending them to the merged PDF. The page order matches the file order you specify.



All processing happens client-side using WebAssembly and JavaScript. After merging, the tool generates the combined PDF as a downloadable blob. File size limits depend only on your device's available memory—the browser can typically handle PDFs totaling several hundred megabytes before performance degrades.

1. Contract & Document Assembly
Legal professionals combine multiple contract sections, exhibits, appendices, and signature pages into single complete agreements. Merge cover letters with resumes, NDAs with project proposals, or terms of service with privacy policies. Single-file contracts simplify distribution, signing workflows, and archival storage.



2. Report Compilation
Researchers, students, and analysts merge multiple report sections written by different team members into unified documents. Combine executive summary, methodology, findings, appendices, and bibliography PDFs into cohesive reports. Ensures consistent formatting and page numbering across collaborative projects.



3. Invoice & Receipt Consolidation
Accountants and bookkeepers merge monthly invoices, receipts, bank statements, and expense reports into single PDF files for easier client sharing or tax filing. Consolidating financial documents reduces attachment counts in emails and simplifies record-keeping for audits or expense reimbursements.



4. Presentation Assembly
Merge slide decks from multiple presenters into single conference presentations. Combine company overview slides, product demonstrations, case studies, and Q&A sections. Unified presentations prevent switching between files during meetings and ensure smooth transitions between topics.



5. E-book & Manual Creation
Authors and technical writers combine chapter PDFs into complete e-books or instruction manuals. Merge table of contents, individual chapters, glossaries, and index pages. Single-file e-books are easier to distribute, read on e-readers, and manage in digital libraries than multi-file collections.

• Order files before merging: The tool merges PDFs in the exact order displayed. Use the up/down arrows to rearrange files before clicking merge. Getting the order right initially saves time versus re-merging with corrected sequence.



• Check page orientation consistency: Merging portrait and landscape PDFs works technically but creates awkward reading experiences. When possible, standardize page orientation across source files before merging for professional-looking results.



• Consider file size for email sharing: Email attachments typically max out at 25MB. If your merged PDF exceeds this, consider compressing it afterward using our Image Compressor or splitting into smaller merged batches. Large PDFs also load slower in email clients and browsers.



• Verify page order after merging: Always open and scroll through the merged PDF to confirm pages appear in correct sequence. Missing pages or incorrect order require re-merging from scratch. Quick verification prevents distributing flawed documents.



• Maintain original files as backups: Don't delete source PDFs after merging. Keep originals for future edits or alternative merge orders. If you need to add, remove, or reorder pages later, having source files readily available saves significant time.



• Use descriptive merged filenames: Default merged filenames are generic. Rename downloads immediately to descriptive names like "Q4-2024-Financial-Report-Complete.pdf" for easy identification in downloads folders or document management systems.



• Merge small batches for testing: When combining many PDFs (10+), test merge a few first to verify compatibility and formatting. Discovering issues after merging all files wastes time. Incremental testing catches problems early.