1. Select PDFs
Drop PDF files here or click to browse
Multiple files — in order listedQuick Guide
- Upload multiple PDF documents.
- Check file order in the list.
- Click Merge to combine them.
- Download the merged result.
FAQ
How many PDFs can I merge?
Your browser RAM is the limit. Most devices handle dozens of files. Large batches may slow.
Can I merge locked PDFs?
No. Remove passwords first. Security prevents merging without credentials.
Does quality degrade?
No. pdf-lib joins object streams. Original quality preserved.
What Merge PDF Does
pdf-lib joins document streams. Pages combine in upload order. No re-encoding happens.
This preserves quality. Zero server bottlenecks. Merge in seconds.
Under the Hood
PDF structure uses cross-reference tables. pdf-lib manipulates these natively in browser JavaScript.
Each page object merges. Links may survive. Bookmarks need recreation.
Edge Cases
Mixed page sizes work. Portrait and landscape combine cleanly. Orientation preserved.
Locked PDFs fail silently. Always unlock before uploading.