Home › Blog › How to Compress a PDF
If you've ever tried to email a scanned contract or upload a document to a government portal, you've probably run into the same wall: the PDF is too big. A 15-page scan from a phone camera can easily hit 30–50MB, while most email providers cap attachments at 25MB and many application portals cap uploads at just 1–5MB. Compressing the file is the fix — and you don't need Adobe Acrobat or any paid software to do it.
Most oversized PDFs aren't bloated by text — they're bloated by images. A scanned page saved at full camera resolution, or a PDF exported straight from a photo-heavy PowerPoint, embeds every image at far higher resolution than a screen or printer actually needs. Compression works by re-encoding those embedded images at a lower resolution and quality, which is invisible to the eye at normal reading distance but makes a massive difference in file size.
| PDF Type | Typical Reduction |
|---|---|
| Scanned document (photos of paper) | 60–85% smaller |
| Photo-heavy presentation export | 50–75% smaller |
| Mostly text, few images | 5–20% smaller |
If your PDF is already mostly text — a Word document exported to PDF, for example — it's likely already efficient, and heavy compression won't help much. The real wins come from documents built out of scanned pages or embedded photos.
ConvertDriver's free PDF compressor runs entirely in your browser — no account, no email, no file ever leaves your device. Here's the process:
If the result is still too large for your upload limit, run it again at a higher compression level, or split it first with our Split PDF tool and send only the pages you actually need.
Because browser-based compression re-renders each page as an image to achieve the biggest size reduction, any selectable or searchable text in the original PDF becomes part of the image. This is usually a non-issue for scanned documents (which typically aren't selectable to begin with), but worth knowing if your PDF is text-heavy and you need to preserve copy-paste or search functionality.