Embed file attachments

Most desktop readers do, and many browser viewers do not. Acrobat, Apple's Preview, Foxit and Okular all list embedded files in a sidebar — usually behind a paperclip icon — and let you open or save them from there. Viewers built into browsers, and some lightweight mobile readers, often ignore embedded files entirely and show the pages with no hint that anything is attached. The checkbox on the card sets the document's page-mode flag, which asks a reader to open its attachments panel as soon as the file is opened: readers that honour it show the list straight away, and readers that do not simply open the document normally. Because of that split, it is worth mentioning the attachments in a covering note rather than assuming your recipient will spot them.

Roughly the size of the original plus the size of everything you attach. Attached files are stored byte for byte — nothing is re-compressed, resized or converted — so a 2 MB report carrying a 15 MB spreadsheet comes out around 17 MB, plus a little structural overhead. The card shows a running "Total to add" figure under the list before you commit, which is the number to weigh against whatever mailbox limit you are up against. If that total is uncomfortable, the effective fix is to zip the companion files first and attach the single archive, since compression is precisely what this tool does not do. Everything is held in memory during embedding, so very large attachments are slower on a phone than on a desktop.

Embed file attachments can only add files — it cannot remove or replace an attachment that is already inside the PDF. Files already embedded in the PDF you drop in are detected, listed under "Already in PDF", marked read-only and carried through to the output untouched; new ones sit alongside them rather than replacing them. That includes matching names, so attaching an updated spreadsheet under a name that already exists leaves both versions inside the document, which is confusing for whoever opens it later. Deleting or overwriting an existing attachment needs a desktop editor such as Acrobat. Within a session you can freely take files out of the pending list with the Remove button before saving — that only affects what has not been written into the document yet, never what was already there.

Any file type is accepted: spreadsheets, CSVs, images, archives, source code, other PDFs, anything at all. Each attachment keeps its original filename, its byte size and its last-modified date, and is labelled with a media type taken from what your browser reports, falling back to a lookup on the file extension and finally to a generic binary type when neither is known. That label is what tells a reader whether to offer "open in a spreadsheet app" or just a save dialog. Two caveats are worth knowing: some mail gateways and document systems strip or quarantine PDFs containing executables or archives, and a reader will not run an attached file for you — it hands it to your operating system like any other download.

Nothing is uploaded — not the PDF, and not the files you attach to it. Each companion file is read from your disk into the browser tab, copied into the document's embedded-files table there, and the finished PDF is written to your downloads with a -with-attachments suffix. That is the whole journey. It matters here more than for most tools, because the files people attach tend to be the raw material behind a document: ledgers, exports, datasets, signed originals. None of it is transmitted, stored or scanned. To confirm it, run the job with DevTools open on the Network tab, or disconnect the network once the page has loaded — the tool still works.

It is free, with no account, no cap on the number of attachments and no premium tier. There is one small thing it writes that we would rather state than have you discover: each file this tool embeds is given a short description noting that it was attached with PDFChamp and on which date. That text appears in the description column of a reader's attachment panel — it is metadata about the attachment, not a change to your pages, and it is the only trace the tool leaves. Nothing is stamped onto a page, no watermark is applied and the document's own metadata is left alone. If you would rather not carry that line, a desktop editor can clear the description afterwards.