How to Reduce a PDF File Size Below 100KB

Government portals, exam application forms, and some job sites often cap file uploads at 100KB, 200KB, or 500KB — sizes that a normal scanned document blows past instantly. Getting under these limits without making the document unreadable takes a specific approach.

Why the strict limit exists

These portals are usually built to handle huge volumes of uploads, so they cap file size to keep their systems fast and storage costs low. The limit isn't about your document's importance — it's a technical constraint you have to work around.

Step-by-step: getting under 100KB

• Start with the smallest reasonable scan resolution — 150–200 DPI is usually plenty for text documents; you don't need 300+ DPI.
• Crop out unnecessary white margins using a tool like Crop PDF — less canvas area means fewer bytes.
• Run the file through a compressor set to maximum compression.
• If it's still too large, check whether the portal accepts JPG instead of PDF — converting a single scanned page to JPG (via PDF to JPG) is often smaller than a PDF wrapper around the same image.
• For multi-page documents with a strict per-file limit, consider splitting into separate files if the portal allows multiple uploads.

What to do if it's still too big

If maximum compression still leaves you over the limit, the image itself is likely still too high-resolution or in color when it doesn't need to be. Converting a scanned photo ID or signature to grayscale before compressing can shave off significant size, since color data adds considerable weight to scanned images.