"Split" and "extract" get used interchangeably, but the tools behind them answer two different questions: do you want everything, broken apart, or do you want just the parts you asked for? Picking the wrong one means an extra cleanup step you didn't need.
What Split PDF actually does
Splitting takes a PDF and breaks it into multiple output files, covering every page in the original. Depending on how you configure it, that might mean one file per page, or several files each covering a range — but the union of every output file is the entire original document. Nothing is left out. This is the right tool when you need to divide a document, not filter it — for example, splitting a 100-page scanned book into 10-page chunks for easier emailing.
What Extract Pages actually does
Extracting pages does the opposite: you pick specific pages — say, pages 4, 9, and 12 through 15 — and get back a single new PDF containing only those pages, in the order you chose. Everything else in the original document is discarded. This is the right tool when you only care about a subset of a larger document — pulling the signature page and the exhibit out of a 40-page contract, for instance, without the rest of it.
A quick way to decide
Ask whether you want to keep everything, just reorganized, or whether you want to throw most of the document away and keep a handful of pages. The first is splitting. The second is extracting. If you're not sure, extracting is usually the safer default — you can always re-combine extracted pages later, but recovering a discarded page from a split you didn't mean to do means going back to the original file.
Both run entirely in your browser
Neither operation needs your file to leave your device — both work directly on the PDF's page structure using pdf-lib, copying the pages you want into a new document without re-encoding any content.
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