Compress a PDF in your browser

Why “compress PDF” sites usually want the upload

Most free compressors ask you to send the document to a data center, wait in a queue, then download a copy that may live on a disk for minutes or days. That is a poor fit for tax returns, offer letters, medical forms, and anything with an account number on it.

PDF Boost AI takes a different path. Each page is rendered in this tab, encoded as a compact JPEG at the quality you chose, and written into a new PDF with pdf-lib. The work happens on the device you already trust. If you close the tab, the file is gone.

This flattening approach is especially effective on scans and photographed pages, which are the files that blow past email caps. On a born-digital text PDF the savings are smaller — and sometimes the compressed copy is not smaller at all. We still show you the size so you can keep the original.

Strong, Balanced, or High — what to pick

Strong targets email and chat. It downsamples aggressively. Use it when the recipient needs to read the page, not archive a print-ready master.

Balanced is the default for a reason: contracts, invoices, and packets still look crisp on a laptop, and the file usually drops enough to attach without a link.

High quality keeps more detail for decks and design proofs. If the download is larger than the original, keep the original. Compression is a trade, not a magic spell.

A 3-page phone scan at Strong often lands well under a few megabytes. A 2-page text export may barely move. That is expected — there was nothing heavy to throw away.

Limits, quality, and when not to flatten

Browser memory is finite. Free processes up to 3 pages per file, while Pro processes up to 80. Every file is also capped at 80 MB so an oversized scan does not freeze the tab. Split larger packets first, then compress each part.

Flattening replaces vector text with pixels. If you still need to select, search, or screen-read the document, compress is the wrong tool — use it on scans, not on a live contract you intend to edit.

Nothing here phones home. There is no account, no queue, and no “we delete files after 2 hours” promise, because the file never left.

Questions

Is this really free, and is there a watermark?

The tool is free. PDF Boost AI does not stamp a watermark on compressed files. Advertisement slots on the page are reserved placements and sit away from the Download button.

Will compression reduce quality?

Yes, by design — you pick how much. Strong is more lossy than High. Open the download and check a detailed page before you send anything final.

Do you upload my PDF?

No. Compress runs locally. If you never press a button, nothing is read. If you close the tab, the bytes are gone.

What are the page and file-size limits?

Free processes up to 3 pages per file; Pro processes up to 80. A file can be up to 80 MB on either plan. Split larger packets first.