How do I delete pages from a 450-page scanned PDF on my phone when the thumbnails load so slowly?

Why the thumbnails are the slow part

Each thumbnail is a real drawing of the page inside your browser. In a scanned file every page is a large image, so 450 pages means 450 drawing jobs on a phone processor. The progress bar shows how far it has got. But drawing is only for display, and selecting does not depend on it: the page slots all exist from the moment the file opens, and the field selects them by number.

The fastest route for a big file

1. Open Delete PDF pages and choose the file, waiting only until its page count appears.
2. Work out the page numbers to delete from the table of contents or by flicking through the file in your reader.
3. Type them into the field: a range with a dash such as 3-40, and single pages with a comma or a space such as 200.
4. Check the summary. You do not need to see every thumbnail, only confirm the numbers and the remaining count.
5. Press the delete and download button and keep the page open until the download starts.

The limits worth knowing

• The tested limit is one file up to 500 pages and 100 MB. A 450-page file is within the page limit, but check its size too, since a high resolution scan can go past 100 MB.
• Building the new file needs memory, because the browser holds the original and the result at the same time. On a phone with limited memory, close other tabs and apps before pressing download.
• If the browser stalls or reloads the page, a computer is the practical answer. Your original file is not affected by a failed attempt.
• The tool does not compress the remaining pages, so the size only drops by roughly what the deleted pages contained.

When splitting beats deleting

If you are keeping a small part of the file, say 20 pages out of 450, typing 430 pages to delete makes no sense. Extract the pages you want with Split PDF instead. The simple rule: type the shorter list. If what you remove is smaller than what you keep, delete; otherwise, split.