About this tool
Merge PDFs in Your Browser
Drop two or more PDFs in the order you want them combined and download a single file with every page in sequence. Runs locally in your browser. No upload, no server processing, no account required.
Why use OmegaPix
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Lossless merge : Each input PDF's pages are copied byte-for-byte into the output. No re-rendering, no quality loss, fonts and vector graphics preserved.
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Any number of files : Combine 2, 20, or 200 PDFs in one pass. The memory guard prevents browser crashes on very large batches.
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Nothing uploads : pdf-lib runs in your browser via WebAssembly. Your contracts, statements, and scanned documents never reach a server.
How it works
Drop your PDFs
Add files in the order you want them in the final document. Drop more anytime. The queue is open until you click Merge.
Confirm the order
Each file shows its position number. Remove and re-add a file to change the order.
Download merged.pdf
One PDF with every input's pages, in sequence. Page count, file size, and download appear in the result panel.
Frequently asked questions
How many PDFs can I merge at once?
No hard limit. The memory guard caps the total at 500 MB on desktop and 200 MB on mobile. That's typically 100+ small PDFs or 10-20 large ones.
Will the merge preserve fonts?
Yes. Each source PDF's embedded fonts are copied alongside its pages. Text remains text, not images.
Does merging compress the PDFs?
No. The output is the sum of inputs plus a small overhead. To shrink, run the merged output through the PDF Compressor afterwards.
Can I re-order files after dropping them?
Not yet, for now, remove a file and re-add it at the right position. Drag-to-reorder is on the roadmap.
What about password-protected PDFs?
They need to be unlocked first. The tool reports "Password-protected" if it encounters one and refuses to merge silently.
Are bookmarks and the table of contents preserved?
No. Document-level navigation is dropped during merge. The page content itself is preserved exactly.
Is anything uploaded?
No. Verify in DevTools → Network during a merge. There are no upload requests.
How big can each PDF be?
Up to 200 MB per file on desktop, 75 MB on mobile. The memory guard prevents browser crashes on very large files.
Will form fields work after merge?
Form fields with unique names work. Fields with the same name across files can collide, flatten forms first if you need them preserved.
Can I merge images and PDFs together?
Not in this tool. Run images through Images to PDF first, then merge the result with the other PDFs here.
When to use this tool
Combine signed contract pages
When each signer returns their page as a separate PDF, merge them into one document for filing.
Bundle bank statements
Merge 12 monthly statements into one year-end PDF for taxes.
Submission packets
Cover letter + résumé + portfolio + references, combine into a single PDF for clean delivery.
When not to use this tool
Encrypted source PDFs
Locked PDFs need to be unlocked before merging, the encryption layer prevents page copying.
You need bookmarks preserved
pdf-lib copies pages but drops document-level bookmarks. For complex documents with navigation, a dedicated PDF editor is better.
PDF forms with shared field names
Merging two filled forms with the same field names can cause field collisions. Flatten forms first if this matters.
Technical details
How merge works under the hood
pdf-lib's PDFDocument.copyPages() walks each source PDF's object graph, copies referenced fonts/images/page-content streams, and re-emits them in a new document. Cross-references are rebuilt cleanly. The result is a fresh PDF with valid structure, not a Frankenstein concatenation.
Page ordering
Files merge in the order you added them, first file's pages first, second file's pages next, and so on. Within each file, pages stay in their original order. To re-order, remove a file from the queue and re-add it at the desired position.
Output file size
Typically the sum of input sizes plus ~5% overhead for the new cross-reference table. Object stream compression is enabled so the overhead is minimal. A 10 MB + 15 MB merge usually produces a 26-27 MB output.
What gets preserved
Page content (text, fonts, images, vector graphics), page-level annotations, form fields with unique names, links within pages. What gets dropped: document-level metadata, bookmarks/outlines, document-level JavaScript, attached files at the document level.
Your files stay on your device
pdf-lib runs entirely in your browser. Source PDFs are read into memory, copied, and emitted as a new file locally. No upload, no server step. Open DevTools → Network during a merge: zero outgoing requests carry PDF bytes.