Word to PDF

How Word to PDF works

The file is read with a FileReader, rewritten in memory and offered as a download. This is why large PDFs are limited by your device's RAM rather than by an upload size limit. A 200 MB scan never crosses the network, so the slowest part is your own disk.

That is the whole architecture: static files, one script, no upload endpoint to leak or log. Close the tab and the work is gone.

What a .docx actually contains

A .docx is a zip archive. Inside it, word/document.xml holds the body as a tree of paragraphs, and each paragraph holds runs of text with formatting. There is no page in the file at all: pagination happens when a program lays the text out.

That is why converting here means reading the paragraph tree and doing the pagination yourself: wrapping each paragraph to the width of an A4 page at the chosen size, and starting a new page when the baseline reaches the bottom margin.

What survives and what does not

Kept: paragraph order, line breaks, headings (a larger bold face), and proper word wrapping — so a long sentence never runs off the page. Dropped: images, tables, columns, text boxes, footnotes, colours, and the original typeface.

That trade is the honest one. A browser cannot reproduce Word's layout engine, and pretending otherwise produces a PDF that looks broken. If the document must look identical, Word's own Save as PDF is the right tool and this page says so.

Why bother, then

Because the common job is a text document that has to become a fixed-layout file: a CV, a cover letter, a quotation, a set of notes. Those are paragraphs and headings, and they convert cleanly in under a second without opening Word or sending a file anywhere.

The PDF is written by pdf-lib with real page breaks, so printing gives exactly what the preview shows.

Good to know

• Works offline once loaded, including on flights and in locked-down networks.
• No file size limit beyond your device's own memory.
• Free to use, with no account and no usage counter.
• Results are produced locally, so they are not logged or shared with anyone.

Questions