How to Compress a PDF to 100 KB for Online Form Uploads

Updated 2026-08-18 · 4 min read

Almost every Indian application portal — exam boards (SSC, UPSC, state PSCs), university admissions, bank KYC and passport/visa sites — sets a strict upload limit, often between 50 KB and 200 KB per document. A phone photo or a scanned certificate is usually far bigger, so the upload gets rejected. Here's how to shrink any PDF under 100 KB in a few seconds.

The quickest way (no software to install)

1. Open the Compress PDF tool.
2. Drop in your PDF (drag it, or tap to browse on mobile).
3. Choose Strong — smallest size.
4. Click Compress PDF and download the smaller file.

Your file is processed over an encrypted connection and deleted automatically within an hour — nothing is stored.

If it's still above the limit

Some documents (especially colour photo scans) are stubborn. Try these, in order:

• Scan in grayscale, not colour. A grayscale scan is often 2–3× smaller. If you already have a colour scan, re-scan or re-shoot it in grayscale.
• Lower the scan resolution. 150–200 DPI is plenty for form uploads; 600 DPI is overkill and huge. Most scanner apps let you pick.
• Crop tight. Trim empty margins before saving — less page area means fewer bytes.
• One page per file. If the portal asks for a single document, make sure you're not accidentally uploading a multi-page scan.

Hitting an exact size (50 KB, 100 KB, 200 KB)

Portals differ. Run Compress once on Strong, check the size, and if you're still over, apply the grayscale + lower-DPI tips above and compress again. Working backwards from the source scan gives far better results than compressing an already-huge file.

Is compressing safe for official documents?

Yes. Compression reduces the image data in the PDF — the text and layout stay intact and readable. For form uploads that's exactly what portals expect. Keep your original high-quality file as a backup.

FAQ