How to Compress a PDF to 100 KB, 200 KB, 500 KB or 1 MB

Application, exam, visa and government portals often set very small limits, such as 100 KB, 200 KB, 500 KB or 1 MB per document. They receive huge numbers of uploads and keep storage and bandwidth costs down by restricting file size. The limit is strict: a 105 KB file is rejected by a 100 KB field just as firmly as a 5 MB file.

Hitting these targets is usually possible, but it takes a methodical approach rather than a single click, especially when the document is a scan or a photo.

How small a PDF can go depends on what is inside it. As a rough guide:

• A one-page text document exported from Word: typically well under 100 KB already.
• A one-page scan or phone photo of a document: often 1 to 5 MB, and usually reducible to 100 to 300 KB with strong compression.
• A multi-page scan: each page adds size, so a 10-page scan under 200 KB is difficult without removing pages.
• A photo-heavy brochure: may not reach 100 KB while staying readable.

Compress PDF has three levels. Low keeps color images at 220 DPI, Recommended reduces them to 150 DPI and High to 96 DPI, which is still readable on screen. Start light and step up only if needed, so you keep as much quality as the limit allows.

1. Open Compress PDF and select your file.
2. Choose Recommended and run the compression.
3. Check the compressed size shown on the result against your portal's limit.
4. If it is still too large, run the original file again with High compression.
5. Open the result and confirm every word is still readable at normal zoom.

Every page adds size. If the portal asks for a single certificate, do not upload the whole 12-page scan. Use Delete PDF Pages to remove cover sheets, blank pages and anything not requested, or Split PDF to extract only the required pages. Then compress the smaller file.

If you photographed a document with your phone, the original image may be 12 megapixels or more, far more detail than a portal needs. You will get a smaller and clearer PDF by improving the source image than by compressing a huge one.

• Crop the photo tightly to the edges of the document so no background is included.
• Resize the image in your phone's photo editor or an image tool before converting it.
• Scan in grayscale at 150 to 200 DPI for text documents rather than color at 300 DPI or more.
• Convert the prepared image with Images to PDF, then compress the PDF if necessary.

Some portals let you upload several files but limit each one. In that case, split a long document into parts with Split PDF, then compress each part. Name the parts clearly so the reviewer can follow the order.

A file that meets the limit but cannot be read will still be rejected, sometimes weeks later. Before uploading, open the final PDF on the device you are using and zoom to 100%. Make sure names, dates, ID numbers, stamps and signatures are all legible. If they are not, go back to Step 2 or Step 3 and reduce content rather than compressing harder.