Merge, split and rotate PDF files

Merging PDF files

Merging combines several documents into one, preserving each page exactly as it was. It is the fix for the situation almost everyone hits eventually: a form, two scanned ID pages and a bank statement that need to arrive as a single attachment because the portal only accepts one file.

Order is the part people get wrong. Add every file first, then arrange the list before merging. Each row shows its position on the left, and you can drag a row or use the arrow buttons to move it. All pages within a file stay together — if you need to interleave pages from different documents, split them first and merge the pieces.

Merging is lossless. Pages are copied structurally, so embedded fonts, vector artwork and photographs come across untouched. A merged page is exactly as sharp and as selectable as it was in its original document, which is why merging is always preferable to the common workaround of printing to PDF.

Naming the result

The download is called merged.pdf. Rename it to something meaningful before you send it — lease-application-complete.pdf reads better in an inbox than a generic filename, and reduces the chance of the recipient losing it among five other attachments with the same name.

Splitting and extracting pages

Splitting pulls specific pages into a new document. Use it to send one section of a long report, remove a page you should not be circulating, or break a scanned batch into per-document files.

Page ranges accept three forms, which can be mixed freely:

• 7 — a single page
• 1-5 — an inclusive range
• 1-3, 7, 10-12 — any combination, separated by commas

Order is preserved exactly as you type it. Entering 5, 1, 3 produces a three-page document in that sequence, which is a quick way to reorder pages without any dedicated reordering step. A descending range such as 9-1 reverses those pages — useful for scans that came out back to front.

To remove pages rather than keep them, list everything except the ones you are dropping. Removing page 4 of a 10-page document means entering 1-3, 5-10.

Fixing a sideways scan

Scanners and phone cameras frequently produce PDFs where the page content is rotated ninety degrees. Rotating here writes the correct orientation flag into the page, which is how the PDF format itself records rotation.

This matters more than it sounds. The common alternative — screenshotting each page and rebuilding the document from images — destroys the text layer. The result cannot be searched, cannot be copied from, cannot be read by a screen reader, and balloons in size. Rotating the page properly keeps everything intact.

The rotation is cumulative and applies to every page in the file. If a document has mixed orientations, split it into the differently-oriented parts, rotate each, and merge them back together.

Why in-browser matters for documents

Images are one thing. PDFs are usually worse: contracts, medical letters, bank statements, passport scans, signed agreements. The files people most often need to merge are precisely the files they should be most careful about uploading.

A conventional online PDF tool uploads your document to a server, processes it there and deletes it on a schedule. Even when that is done honestly, you are trusting a company's retention policy, its staff, its logging, its backups and its security posture with a document you would not email to a stranger.

Doing the work in the browser removes the question. The file is read by JavaScript running on your machine, modified in your machine's memory, and written back to your downloads folder. You can verify this yourself: open your browser's developer tools, switch to the network tab, and merge a file. No request carries your document, because there is no request.

Why merged PDFs get large

A merged file is roughly the sum of its parts, and scanned pages are the usual reason that sum is uncomfortable. A scan is a photograph of a page — often a full-colour one at 300 dpi, which is around 25 megapixels per sheet. Ten such pages can easily exceed 50 MB.

Three things reliably help, in order of effect:

• Scan in greyscale or black and white. Unless the document has meaningful colour, this alone often cuts the size by two thirds.
• Scan at 200 dpi rather than 600. 200 is comfortably enough for text to stay crisp and legible; 600 is for archival reproduction of photographs.
• Compress the images before they become a PDF. If your scanner produces JPEGs first, run them through the image compressor and then assemble the PDF.

If you are already holding an oversized PDF and cannot rescan, splitting it into two or three smaller documents is usually more practical than fighting an email attachment limit.

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