How to reduce a PDF file size (under 1 MB, 200 KB or 100 KB)

What makes a PDF large

Text is cheap: a hundred pages of typed text is often under 500 KB. Images are what add weight. A single page scanned by a phone camera at full resolution can be 2–4 MB on its own, because the PDF is really storing a high-resolution photo.

Embedded fonts, duplicate images repeated on every page (such as a logo in the header) and leftover editing data also add size, but they are usually a small share compared to photos and scans.

Step 1: remove pages you do not need

The fastest size reduction is deleting pages. Portals rarely need blank backs of scanned sheets, instruction pages or duplicate copies. Use Delete PDF pages to drop them before compressing.

Step 2: compress the images

Open Compress PDF and start with the lighter setting. It lowers image resolution to around screen quality, which usually cuts scans by 60–90% while text stays legible. Only move to the strongest setting if the file is still over the limit.

If you need a precise target, use the size-specific pages such as Compress PDF to 200 KB or Compress PDF to 100 KB, which aim for that number.

Step 3: if it is still too big

• Rescan at 150–200 DPI in greyscale instead of colour — documents rarely need colour.
• Split the document and upload it in parts if the portal allows multiple files.
• Crop wide scanner borders so less empty image is stored.

Checking the result

Always open the compressed file and zoom in on small print such as dates, signatures and ID numbers. If they are blurry, go back one compression step. A rejected application because of unreadable text costs more time than a slightly larger file.

Is it safe to compress private documents online?

With avalpdf the compression runs inside your browser tab, so your file is never uploaded. That matters for ID cards, salary slips and certificates, which are exactly the documents portals ask for.