A PDF that won't attach to an email, or blows past a portal's upload limit, is one of the most common file annoyances there is. Before you reach for the Compress PDF tool, it helps to know why a PDF got big in the first place — because the right fix depends on it.
1. Figure out what's actually taking up the space
Two very different PDFs can both be "20MB":
- A scanned document — every page is really a photograph, often at a much higher resolution than needed for reading on screen.
- A design-heavy document — vector graphics, embedded fonts, and a few high-res images mixed with real, selectable text.
Scanned PDFs compress dramatically well, because you can drop the image resolution a long way before a human notices. Text-heavy PDFs compress much less, because the text itself is already tiny — the size is coming from a handful of images you may want to keep sharp.
2. Match the compression level to the use case
Our Compress PDF tool re-renders each page at a chosen resolution and JPEG quality — think of the three presets as:
- Light — for a document someone will read closely on screen. Barely visible quality loss, modest size savings.
- Medium — the right default for "email this contract" or "upload this to a portal." Good balance.
- Strong — for archival copies or a scanned form where you just need the text to be legible, not beautiful.
3. Know the one real trade-off
Because there's no server here to run a proper PDF stream optimizer, browser-based compression works by re-rendering each page as an image. That means the output PDF's text is no longer selectable or searchable — you're trading that away for the size reduction. For a scanned document that was never selectable text anyway, you lose nothing. For a Word-export PDF full of real text, that's worth knowing before you send it on.
4. Split before you compress
If only a few pages are actually large — say, three photo pages in an otherwise-text report — pulling just those pages out with Split PDF, compressing only those, then merging them back with Merge PDF, keeps the rest of your document's text fully intact.
5. Convert to images last, not first
If you only need a couple of pages as pictures (for a slide deck, say), use PDF to Images directly rather than compressing the whole PDF and re-extracting — you'll get a cleaner result at exactly the resolution you choose.