How to Compress a PDF to 100 KB or 200 KB for Online Forms

You are filling an online application, and the upload box says "Maximum file size: 100 KB". Your scanned marksheet is 2.4 MB. This happens on many job, exam, scholarship and government portals. The good news: almost any document can be brought under 100 KB or 200 KB and still be perfectly readable, if you know where the size comes from.

Quick answer: open Compress PDF, add your file and choose Strong. If it is still above the limit, convert the pages to images, compress them to a target size, and turn them back into a PDF (method 2 below).

Why is my PDF so big?

A PDF made from a scanner or a phone camera is really a set of photos, one per page. Their size depends on three things:

• Resolution: a page scanned at 600 DPI has 9 times more pixels than one at 200 DPI.
• Colour: a colour scan is much larger than a greyscale or black-and-white scan of the same page.
• Number of pages: every extra page adds another photo.

Text documents created on a computer (for example a resume exported from Word) are usually small already. If such a file is large, it normally contains big images or embedded scans.

Method 1: Compress the PDF directly

This is the fastest way and works for most files.

1. Open the free Compress PDF tool.
2. Drop your PDF in the box (you can add several files at once).
3. Choose a level:
   • Light keeps the best quality with smaller savings.
   • Balanced is right for most documents.
   • Strong gives the smallest file, good for scans that have to go under 100–200 KB.
4. Press Compress PDF and look at the new size shown under the result.
5. Download the file and open it once to check that every line is still readable.

Method 2: Get under an exact limit (100 KB, 200 KB)

When a portal has a strict limit and Strong compression is not enough, rebuild the PDF from compressed images. This gives you full control over the final size.

1. Turn the pages into images with PDF to JPG.
2. Compress each image to a target size with Compress Image to KB. Choose 20, 50 or 100 KB, or type your own target. For a 100 KB PDF with two pages, aim for about 45 KB per page so there is a little room left.
3. Put the pages back together with JPG to PDF. Choose A4 and a small margin.
4. Check the final size. If it is still slightly too big, lower the target a little and repeat step 2.

Rough size guide

These are typical results for an A4 page of normal text. Photos and coloured certificates need more.

Make the file smaller before you compress

A few simple steps often save more space than compression itself:

• Scan at 150–200 DPI. That is sharp enough for any form. 300 DPI and above only makes files bigger.
• Use greyscale for text documents such as marksheets, salary slips and letters.
• Upload only the pages they ask for. Use Split PDF or Organize PDF to remove extra pages.
• Crop the white border around a scanned page with Crop PDF.
• Combine pages into one file with Merge PDF only when the portal asks for a single PDF, then compress once at the end.

Common upload problems and fixes

Also keep file names simple, like marksheet-10th.pdf. Some older portals reject names with spaces or special characters.

Is it safe to compress certificates online?

Fileora shows on every tool page where your file is processed. Browser tools such as PDF to JPG, Compress Image and JPG to PDF work on your own device and never upload anything. Compress PDF uses Fileora's processing server for the best results; files are sent over an encrypted connection and deleted automatically within an hour.

Frequently asked questions