Merge PDF.

Upload your PDF files to HQCalc's PDF Merger, drag to reorder them as needed, optionally set page ranges for each file, then click Merge. The merged PDF downloads instantly — no account, no watermark, no cost.

With HQCalc, it is completely safe. All PDF processing happens locally in your browser using the pdf-lib JavaScript library. Your files are never uploaded to any server, never stored, and never transmitted. They remain on your device at all times.

Yes. HQCalc merges PDFs by directly copying page objects from the source documents into a new PDF using pdf-lib. There is no re-rendering, re-compression, or quality loss — the merged output is byte-for-byte identical to the source pages.

Yes. Each file in HQCalc's merger has a page range input field. Enter ranges like '1-3, 5, 7-10' to include only specific pages. Leave it blank to include all pages. This lets you precisely control which pages from each document appear in the merged output.

In HQCalc's PDF Merger, you can drag and drop files in the list to reorder them. You can also use the up/down arrow buttons beside each file. The merged PDF will follow the order shown in the list from top to bottom.

Yes. Each file has a rotate button (↺) that applies 90° clockwise rotation to all pages from that file. Click multiple times for 180° or 270° rotation. The current rotation angle is shown as a badge on the file entry.

There is no server-side limit since all processing happens in your browser. Practical limits depend on your device's available RAM. Most devices handle dozens of PDFs and hundreds of pages without issue. Very large files (100MB+) may be slow depending on your hardware.

Not directly. Password-protected PDFs must be unlocked (decrypted) before they can be merged. Open the PDF in any PDF viewer, remove the password protection and save it, then upload the unlocked version to HQCalc's merger.

pdf-lib is an open-source JavaScript library for creating and modifying PDF documents in the browser. HQCalc loads pdf-lib directly in your browser to perform all merging operations locally on your device, eliminating any need for server infrastructure.

Never. HQCalc adds no watermarks, no branding, and no modifications to your content. The merged PDF contains only your original pages, exactly as they were in the source documents.

Yes, there is no hard limit on the number of files. Add as many PDFs as needed. They will be merged in the order shown in the file list, which you can adjust by dragging.

For each file in the list, enter a page range in the text field below the filename. For example: '1, 3-5' to include pages 1, 3, 4, and 5. Each file can have its own independent page range. Combined with drag-to-reorder, you can build any custom page sequence.

Yes. HQCalc's PDF Merger is fully responsive and works on modern mobile browsers (Chrome, Safari, Firefox on iOS and Android). The pdf-lib library is supported on all current mobile platforms.

pdf-lib creates PDF 1.7 compliant documents, which is the current widely-supported standard. The merged file is compatible with all modern PDF readers including Adobe Acrobat, Preview (macOS), Chrome's built-in viewer, and mobile PDF apps.

Yes. HQCalc merges all PDF types — text-based, image-based (scanned), or mixed. Scanned pages are copied as-is with no OCR or re-rendering. The output will be the same type as the input (scanned pages remain image-based).

Adobe Acrobat is a paid desktop application. HQCalc's PDF Merger is free, browser-based, requires no installation, and processes files locally for complete privacy. While Acrobat offers more advanced editing features, for basic merging, reordering, and page selection, HQCalc provides equivalent functionality at zero cost.

There is no undo within the tool, but since your original files are never modified, simply re-add them to start over. The merged PDF is a new separate file; your source PDFs remain intact.

HQCalc copies page content directly without re-rendering, so visual differences are rare. If you notice differences, they may be due to missing embedded fonts or custom PDF features. Try updating your PDF viewer, or check if the source PDFs use non-standard fonts.

The merger doesn't split PDFs, but you can effectively extract specific pages: add a single PDF, set the page range to only the pages you want, and click merge. The output will contain only those pages.

No. HQCalc never stores, transmits, or accesses your PDF files. Everything runs in your browser. When you close the tab, all data is cleared from memory automatically.