Compress PDF to 100 KB

Many government and exam forms set a 100 KB maximum for a document upload. This guide shows how to reach that limit with the free PDF Compress tool, how to verify the exact file size, and what to do when a PDF will not go below 100 KB without losing readability.

100 KB is a common example, not a universal rule. Check your own form's upload screen first: the format, maximum size and page count it actually asks for. Some portals count 1 KB as 1024 bytes, others loosely as 1000 bytes; staying clearly below the limit avoids that ambiguity.

Step by step: reach a 100 KB limit

Keep the original certificate or marksheet PDF safe. Work on a copy.
Open PDF Compress and select or drop your PDF. The file stays on your device; nothing is uploaded.
Enter 100 in the "Form maximum (KB, optional)" box. The tool checks the result against your limit using 1 KB = 1024 bytes; it is a check, not an exact-size target.
Start with the light setting for the best detail, especially for small text, stamps and signatures.
Download the -compressed.pdf file and check its actual bytes/KB in your file details.
If it is above 100 KB, retry from the original with the middle setting. Use the strongest setting only if the final text and stamps remain readable.

Compression turns each page into a photo, so text in the compressed PDF can no longer be selected or copied. For scanned documents this is usually fine; for a PDF you need to search or copy from, weigh that trade-off.

When the PDF is still above 100 KB

Check whether the form needs every page. Remove unneeded pages first with PDF Split, then compress the smaller file.
A one-page scan with heavy photos may not reach 100 KB readably. Rescan at a lower resolution if you can, or crop empty margins with Crop PDF before compressing.
Do not rename a JPG to .pdf or the other way round; that changes the name, not the format, and portals reject it.
Compression can occasionally leave a file about the same size or even larger, especially for already-optimized PDFs. If nothing works, the honest answer is a better source scan, not a fourth compression pass.

Verify before you upload

Open the downloaded file and read the smallest text, stamp and signature on it. If you cannot read them, the portal's reviewer probably cannot either. Check the portal preview after uploading; if it shows a blur or an error, go back one preset. Keep both the original and the compressed copy until the form is finally submitted.

Frequently asked questions

Does the tool compress to exactly 100 KB?

No. It offers three compression presets and an optional 100 KB limit check. You pick the lightest result that stays readable and under your limit, then verify the exact KB in file details.

Is my certificate uploaded anywhere?

No. Compression runs in your browser on your device. The file is not sent to a server.

Why can I no longer select text after compression?

Each page becomes a photo during compression. That is what makes the file small, but selectable text is lost. Keep the original PDF for anything you need to copy from.

The portal still rejects my file. What else can be wrong?

Check the required format (PDF vs JPG), page count, and whether the portal measures KB as 1000 or 1024 bytes. Stay clearly under the limit and confirm the file opens normally before retrying.