How to reorder PDF pages
- Drop your PDF into the zone above, or click to browse. The tool renders a thumbnail of every page — you will see them appear progressively as each one loads.
- Drag thumbnails into the order you want. The number below each thumbnail shows its new position in the output.
- To remove a page entirely, hover the thumbnail and click the × that appears in the top-right corner.
- Click Save reordered PDF. The file downloads instantly with pages in the order shown.
Thumbnails are rendered by pdf.js in your browser. The reordered PDF is assembled by pdf-lib, also in-browser. Your file never leaves your device — open DevTools (F12) → Network while working to confirm zero uploads.
When to reorder PDF pages
- Fixing a mis-scanned document — pages came out of the scanner in the wrong order. Drag them into the correct sequence and download a corrected PDF without rescanning.
- Moving an appendix to the front — a reviewer asks for the summary on page 1 instead of page 12. Drag it there in seconds.
- Interleaving two separately scanned halves — some duplex-scanning workflows produce odd pages and even pages as separate files. Merge them first, then interleave with reorder.
- Removing blank or duplicate pages — click × on any page you want excluded. No need for a dedicated delete tool.
- Rearranging a presentation for a different audience — move the technical deep-dive slides to the end for an executive audience without editing the source file.
- Reorganising a multi-section report — swap the order of sections to match a new structure agreed in review.
How it works under the hood
Loading the PDF triggers pdf.js to parse the document and render each page to an off-screen <canvas> at 25% scale — producing a thumbnail roughly 150 × 210 pixels for a standard A4 page. The thumbnails appear progressively as each page finishes rendering, so you can start reordering before the full document loads.
Internally, the tool keeps an ordered array of page references. Each time you drag a thumbnail to a new position, the array is updated and the grid re-renders. No PDF processing happens during reordering — it is all array manipulation and DOM updates, which is why it feels instant.
When you click Save, pdf-lib loads the original PDF bytes, creates a blank new PDF document, and calls copyPages(sourceDoc, orderedIndices) to copy pages in the order you defined. Each page's content — text, fonts, images, vector graphics, annotations — is copied byte-for-byte without re-rendering. The result is written to a Uint8Array in memory, converted to a Blob, and downloaded.
Limits and what to expect
- Thumbnail load time: rendering thumbnails is CPU-bound. A 100-page PDF takes roughly 5–15 seconds to fully preview on a modern laptop, depending on page complexity. Simple text pages load faster than image-heavy pages.
- Page deletion: pages removed with × are not included in the output. This is equivalent to extracting a subset of pages — the tool doubles as a basic page-deletion utility.
- Password-protected PDFs: the tool attempts to load encrypted PDFs using the
ignoreEncryptionflag. PDFs that require a password to view their content will fail — unlock them in your PDF reader first. - Very large PDFs: documents over 200 pages may take 30–60 seconds to fully thumbnail. The progress bar tracks rendering. You can start dragging pages before all thumbnails are loaded.
- Browser support: Chrome 90+, Firefox 90+, Safari 15+, Edge 90+.
Privacy: what happens to your file
Your PDF is read into browser memory using the File API. Thumbnails are rendered locally by pdf.js. The reordered PDF is assembled locally by pdf-lib. At no point is any data sent to a server.
This matters particularly for PDFs containing confidential content — financial data, legal documents, medical records, internal strategy documents. With upload-based PDF organizers you are trusting a third-party server with that content. With keptlocal the data stays on your machine, and you can verify it by watching the Network tab in DevTools.