How to Compress a PDF to 100 KB or 200 KB (Free)

Why portals limit PDFs to 100 KB or 200 KB

Government portals, exam forms, scholarship sites and job applications receive lakhs of uploads. Small limits keep their storage and bandwidth costs down. They also make pages load on slow mobile connections. So you'll often see rules like "PDF only, maximum 100 KB" for a caste certificate or "up to 200 KB" for a marksheet.

The trouble is that a phone scan of one A4 page can easily be 1–3 MB. That's 10 to 30 times over a 100 KB limit. No tool can squeeze that much without lowering image detail somewhere. The goal is a file that is small enough and still clearly readable.

Note: "100 KB" can mean 100,000 bytes or 102,400 bytes, depending on the website. Aim a little under the limit, around 95 KB or 190 KB, so you pass either way.

Step by step: compress a PDF with our tool

1. Open the PDF compressor. It works in your browser, so nothing is uploaded.
2. Drop your PDF on the page or click to choose it.
3. Under Compression level, pick one of the three quick options:
   • Light (about −20%): best quality, moderate reduction.
   • Medium (about −35%): balanced quality and size.
   • Heavy (about −50%): smallest file, lower quality.
4. For finer control, move the Quality slider (10 to 100) or type a number. Lower values compress harder.
5. Press Compress at quality N. You'll see the before and after sizes and a Download button showing the new size.
6. Not small enough? Use the Not right? Try buttons under the result to switch level, then compress again. Your original is never changed, so you can retry as often as you like.

The percentages on the buttons are rough guides. The real saving depends on what's inside your PDF.

What the Quality slider actually changes

Our compressor uses a page-render method. It draws each page as a picture, saves that picture as a JPG, and builds a new PDF from those pictures. The slider controls two things at once: how many pixels each page gets and the JPG quality.

Here is what that means for one A4 page:

After compressing, the line under the result shows the exact method used, for example "PDF.js render (scale 56%, JPEG 38%)".

Warning: Because every page becomes an image, you can't select, search or copy the text in the compressed PDF. Form fields and links stop working too. Keep your original file for anything that needs text.

There's a second side effect worth knowing. The page dimensions shrink along with the pixels, so a Heavy A4 page comes out about 11.8 cm wide instead of 21 cm. On screen it looks the same once you zoom. If you print it, choose "Fit to page" in the print dialog.

Which level to start with

• Typed documents (offer letters, certificates from a computer): start with Medium. Normal-sized text stays readable at that size.
• Scans and phone photos of documents: start with Heavy. Scans are mostly image data, so they shrink the most.
• Documents with small print (fee receipts, bank statements): stay on Light or Medium and zoom in to check every number after compressing.

If the result says Already well optimised, the PDF is already lean at that quality. Move the slider further left or pick Heavy.

When it still won't go under 100 KB

A useful rule is the per-page budget. Divide the limit by the number of pages. A 5-page PDF with a 100 KB limit gives you about 20 KB per page, or 19 KB if you aim for 95 KB. That's tight for scanned pages, so try these fixes in order.

1. Remove pages you don't need

Blank backs of pages, instruction sheets and duplicate copies all count. Use Split PDF and type the page ranges you want, for example 1-3, 5. Each range downloads as its own PDF. Keep only the pages the portal asked for, then compress again.

If the portal has separate upload slots, split one big file into several smaller ones. Each slot then gets its own 100 KB.

2. Re-scan at a lower resolution

Scanner apps often default to 300 or even 600 DPI in colour. That's far more detail than a form needs. An A4 page at 300 DPI is about 2480 × 3508 pixels, or 8.7 megapixels. At 150 DPI it's about 1240 × 1754, roughly a quarter of the pixels.

For text documents, scan at 150 DPI and choose Grayscale or Black & white. Colour adds data without adding anything useful to a marksheet. Our compressor keeps colour, so grayscale has to happen at scan time.

3. Rebuild the PDF from JPGs with an exact size target

This route gives you the most control, and the text often stays sharper than with Heavy compression.

1. Convert the PDF to images with PDF to JPG. Each page downloads as its own JPG.
2. Add the page images to the Image Resizer. In File size, turn on Make it under a size and type your per-page budget, for example 30 KB. Download them as a ZIP.
3. Combine the small JPGs with JPG to PDF. It places each image on its own page without re-compressing it, so the final PDF is close to the total of the JPG sizes.

Worked example: a 3-page scanned marksheet with a 100 KB limit. Set each page to under 30 KB. Three pages at up to 30 KB each is at most 90 KB of images, which leaves room for the small PDF overhead.

4. Crop away the margins

Big white borders around a scanned page still cost pixels. Crop the scan tightly in your scanner app, or in the Image Resizer's Crop tab in the JPG route above. The same detail then fits in fewer pixels.

Merging several documents into one PDF

Many forms want one PDF that contains, say, your ID proof, address proof and a certificate. Combine them first with Merge PDF. You can reorder the files with the up and down arrows before merging, and the result downloads as merged.pdf.

Then compress the merged file once and check the size against the limit. If it's over, compress each document separately before merging. That lets you use Heavy on a scanned ID card but Medium on a typed letter with small print.

Tip: Have photos instead of PDFs? Put them through JPG to PDF to make one PDF, then compress it. Shrinking the photos first with the Image Resizer usually gives a smaller, cleaner result.

Check the result before you upload

A file that's small but unreadable gets rejected just as surely as one that's too big. Before you upload:

• Check the size in bytes. On Windows, right-click the file and choose Properties. On a Mac, use Get Info. Compare the byte count with the limit, not just the rounded KB figure.
• Zoom to 100% and read every line. Names, roll numbers, dates and amounts must be clear. If anything is fuzzy, go back one level, from Heavy to Medium, and use the split or re-scan tricks instead.
• Open it on your phone. If you can read it on a small screen, the person checking it can too.
• Confirm the page count. Make sure no page went missing when you split or merged.
• Rename it simply. Some portals reject long file names or special characters. Something like marksheet-class12.pdf is safe.

Common mistakes

• Compressing a PDF that's already been compressed. Each round blurs text a bit more. Always start again from the original file.
• Picking the lowest quality straight away. Quality 10 renders an A4 page at only 238 × 337 pixels, which is too small for most text. Step down gradually.
• Uploading a password-protected PDF. Our compressor can't read locked files. Remove the password in the app that created the PDF first.
• Forgetting about searchable text. If a recruiter's system searches the text of your CV, don't send a compressed copy that's become images. CVs made in a word processor are usually small enough already.