Why this uses Mozilla's own PDF engine, not a custom one#
PDF is a genuinely complex format — vector paths, embedded fonts with custom encodings, layered transparency, color spaces that aren't plain RGB. Getting all of that to render correctly is most of the actual difficulty in a PDF renderer, which is why this tool uses PDF.js, the open-source rendering engine Mozilla built and uses to power Firefox's built-in PDF viewer, rather than attempting a smaller reimplementation. It runs entirely inside your browser tab — the same engine, the same output you would get by opening the PDF directly in Firefox and taking a screenshot of each page.
Why resolution is a real choice, not a fixed setting#
A PDF page doesn't have a native pixel resolution the way a photo does — it's defined in vector units (points), rendered at whatever pixel density you ask for. A low scale produces a small, fast-to-download file suitable for a quick preview; a higher scale renders more pixels per point, producing a sharper image better suited for printing or zooming in, at the cost of a larger file. This tool lets you pick that trade-off directly instead of guessing at a fixed resolution that is wrong for your use case half the time.
Where this differs from PDF to Text#
This tool produces a picture of each page — useful when you need the visual layout preserved exactly, want to drop a page into an image editor, or need a thumbnail. If what you actually need is the words on the page as editable, searchable text, this site's PDF to Text Converter extracts that directly instead of turning the page into an image you would then have to read visually.