Choose a PDF action to begin.
Image & PDF Tools
PDF Merger & Compressor
Merge multiple PDFs and optimize PDF structure from your browser with no upload required. Free, fast, and built for a clean browser workflow.
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About this tool
Combine multiple PDFs into one file for applications, reports, or invoice packs — without uploading sensitive documents to a third-party merge service.
Client-side processing keeps contracts, ID scans, and tax forms on your device while pdf-lib assembles pages in the browser.
Optimization can tidy some PDF structures; image-heavy scans may still stay large unless you recompress images separately first.
Tips for better results
- Order files carefully before merging; page order usually follows the order you add them.
- If a merge fails on a huge scan set, split the job or reduce image DPI with an image tool first.
- Open the downloaded PDF and spot-check the first and last pages before sending it to a client or portal.
- Password-protected PDFs may need unlocking in another app before this browser tool can read them.
How to use
- 1 Choose PDF files to merge or optimize.
- 2 Run the selected PDF action.
- 3 Download the generated PDF file.
FAQ
Are PDFs uploaded?
No. Merge and optimize steps use client-side JavaScript in your browser.
Can it always reduce file size?
Not always. Structure optimization helps some files; photo-heavy PDFs often need image recompression elsewhere.
How many PDFs can I merge?
It depends on browser memory and device capacity. Large batches work better on a desktop with free RAM.
Does merging keep form fields?
Simple page merges are reliable. Complex interactive forms or scripts may not survive every optimization path.
Is there a watermark?
No. ShishwaLab does not add watermarks to merged output.
Can I rearrange pages after merge?
Re-run with files in the desired order, or use a dedicated PDF editor for fine page sorting.