Merge PDF Files Online for Free

Combine multiple PDF files into one document instantly. Free, private, no sign-up, no watermark, and no uploads — everything runs in your browser.

Your PDFs

Drag & drop PDFs here, or

Tip: Use ↑/↓ buttons or drag handle to reorder.

    No files selected.

    Merge & Download

    Keyboard: Ctrl/Cmd + Enter to merge · focus a row/control + Delete removes · Alt + ↑/↓ reorders.

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    How this tool works

    Release Updates

    v1.1 (February 10, 2026)

    • Added duplicate file detection (name + size + lastModified) with a user confirm prompt.
    • Added merge options: output filename, auto-open after download, and optional page ranges per file.
    • Improved resilience for encrypted/corrupt PDFs with per-file failure reporting and optional skip-failed mode.
    • Added detailed progress text (Processing file X of Y) plus safer size/page-count limits with warnings.
    • Improved accessibility and usability with keyboard reorder shortcuts, drag insertion indicators, and distinct row color cues.
    • Added post-merge actions (Start over / Merge another set) and hardened download URL cleanup.
    • Everything is processed locally on your device using pdf-lib — nothing is uploaded.
    • Reorder by dragging the handle or the arrow buttons.
    • If a PDF is encrypted or corrupted, you can skip failed files and continue merging the rest.

    Why use this free PDF merger?

    Your PDFs stay private

    Files are processed locally in your browser. They are not uploaded to Starlight Tools or any third-party server.

    Merge without watermarks

    The downloaded PDF is your combined document only, with no added branding or watermark.

    Reorder before merging

    Drag files into the order you want, remove files, or use page ranges before creating the final PDF.

    Works on modern browsers

    Use the tool on desktop or mobile browsers without installing PDF software.

    Private PDF merging: no uploads

    Unlike many online PDF mergers, this tool processes files directly in your browser using client-side JavaScript. Your PDFs do not leave your device, and Starlight Tools does not receive, store, or inspect your documents.

    How to Use This PDF Merger Tool

    Merging PDF files is quick and easy with this tool. Just follow these simple steps:

    1. Select PDFs: Click the "Select PDFs" button to choose one or more PDF files from your device. You can also drag and drop files into the list area.
    2. Add More (Optional): If you need to add more PDFs after your initial selection, click the "+ Add More PDFs" button.
    3. Reorder Files: Your selected PDFs will appear in a list. Use the up/down arrows, keyboard shortcuts, or drag-and-drop to change their order in the final merged document.
    4. Choose Page Ranges (Optional): Enter ranges such as 1-3,7 beside a file if you only want selected pages included.
    5. Remove Files (Optional): Click the "✖" (cross) button next to any file you wish to remove from the merge list.
    6. Merge and Download: Once your files are in the desired order, click the "Merge PDFs" button. The tool will process the files in your browser, and a "Download Merged PDF" link will appear. Click it to save your combined PDF!

    Privacy Note: All merging happens directly in your browser. Your files are never uploaded to our servers, ensuring your data remains private and secure.

    Common reasons to merge PDFs

    PDF merging is useful whenever separate documents need to become one clean file for sending, archiving, or uploading.

    • Combine invoices into one PDF for bookkeeping or client records.
    • Merge scanned documents into one file after using a scanner or phone app.
    • Join contracts, exhibits, terms, and attachments before sharing.
    • Combine application documents such as forms, IDs, certificates, and supporting evidence.
    • Create one PDF from reports, receipts, statements, or project files.

    Frequently Asked Questions

    Is this PDF merger really free?

    Yes. This PDF merger is free to use in your browser, with no sign-up required and no watermark added to the merged PDF.

    Are my PDF files uploaded?

    No. Files are processed locally in your browser using client-side JavaScript. Starlight Tools does not receive, store, or inspect your PDFs.

    Will the merged PDF have a watermark?

    No. The downloaded PDF contains your combined document only, with no added Starlight Tools branding or watermark.

    Can I reorder PDFs before merging?

    Yes. Reorder files with the arrow buttons, keyboard shortcuts, or drag-and-drop before creating the final PDF.

    Can I merge only selected pages from each PDF?

    Yes. Enter page ranges such as 1-3,7 for individual PDFs if you only want selected pages included.

    Does merging PDFs reduce quality?

    The tool copies pages into a new combined PDF without intentionally compressing or rasterizing them, so normal page quality is preserved.

    Can I merge PDFs on mobile?

    Yes. The tool works in modern mobile browsers, though very large PDF sets are easier to manage on desktop.

    Is there a file size limit?

    Because everything runs in your browser, practical limits depend on your device memory and browser. The tool warns on very large total file sizes and page counts.

    Can I merge password-protected PDFs?

    Encrypted or password-protected PDFs may fail to load. You can enable skip-failed mode to merge the remaining files.

    What should I do if a PDF fails to merge?

    Try removing that file, saving an unlocked copy from your PDF viewer, or keeping skip-failed mode enabled so the other PDFs can still merge.

    5 Fun Facts about Merging PDFs

    Mixed page sizes survive

    A merged PDF can happily mix A4, Letter, or even poster-sized pages—printers will scale each page independently, so watch for surprise zoom levels.

    Layout mashups

    Form fields can mirror

    If two PDFs contain form fields with the same name, they link after merging—typing in one box can auto-fill the “twin” elsewhere in the document.

    Linked forms

    Signatures don’t stay valid

    Digital signatures seal the exact bytes of a PDF. The moment you merge pages, those bytes change—every prior signature is effectively broken.

    Crypto reality

    Page numbers are just drawings

    PDFs don’t have built-in numbering. Those “page 3 of 12” labels are text on the page, so merging won’t renumber them automatically.

    Bring your own numbers

    Hidden OCR rides along

    Scanned PDFs often hide invisible OCR text behind images. Merging keeps that ghost layer, so your combined file stays searchable.

    Invisible ink

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