Compress PDF to 100 KB
The 100 KB target is already set. Add your PDF and get the clearest version that fits under 100 KB, made on your own device.
- 100% free
- No sign-up
- Runs in your browser
- Updated October 2026
1Choose a PDF
2Target size
We aim just under the limit, so the file passes whether the portal counts 1 KB as 1,000 or 1,024 bytes.
3How to compress
Result
Getting a PDF under 100 KB
100 KB is one of the tightest limits you will meet on an upload form. It is common for single certificates, ID proofs and supporting documents on job, exam, scholarship and admission portals, where each file is checked separately. A phone scan of one page is often 1 to 3 MB, so it has to shrink by 90% or more.
This page is set to 100 KB. The tool keeps typed text and lines exactly as they are and makes the pictures smaller, trying settings until the file fits, then raising the quality again as far as the limit allows. You see the size before and after, and a preview of every page.
Think in KB per page
The simplest way to plan for 100 KB is to divide it by the number of pages. One page gets the whole 100 KB; four pages get about 25 KB each. A typed page needs very little, but a scanned page is a picture, and 25 KB is not much for a picture of an A4 sheet. So the fewer scanned pages you upload, the clearer each one can be.
| Pages in the PDF | Room per page at 100 KB | What to do |
|---|---|---|
| 1 | About 100 KB | Usually fine in colour |
| 2 | About 50 KB | Switch on Black and white for scans |
| 3 to 5 | 20 to 33 KB | Black and white, and check small print |
| More than 5 | Under 20 KB | Upload only the pages asked for |
Steps
- Remove extra pages first if the portal wants only page 1 or the front of a certificate. The PDF editor deletes pages in your browser.
- Add the PDF here. 100 KB is already selected. If the PDF has a password, type it when asked.
- Leave the method on Auto unless you must keep the text selectable.
- Turn on Black and white for scans of printed or handwritten pages.
- Press Compress, then zoom into the preview: roll number, name, dates, signature and stamp must be easy to read.
- Download and upload the new file.
When 100 KB is too tight
If a multi-page scan has to fit in 100 KB, Auto may turn the pages into images at a low resolution. The result box tells you the DPI it used. At 75 DPI or less, small print can blur. In that case, splitting the document is better than squeezing it: many portals have separate slots for each certificate. And if the tool says it cannot reach 100 KB at all, believe it rather than forcing a smaller file. An unreadable document can be rejected later, often after the form is locked.
Need a photo or a JPG scan under 100 KB rather than a PDF? Use compress image to 100 KB.
Other target sizes
Need more options? Open the full Compress PDF to 100 KB, 200 KB or 1 MB.
Frequently asked questions
How do I reduce a PDF to under 100 KB?
Add the PDF on this page; 100 KB is already selected. Press Compress and the tool shrinks the pictures inside until the file fits, then shows the new size. Zoom into the preview to check it is readable, then download.
How many pages can fit in 100 KB?
It depends on the pages. A typed page with no pictures takes very little, so many pages can fit. A scanned page is one picture, so 100 KB leaves room for only a few scanned pages at a readable quality, fewer in colour. Black and white helps a lot.
My PDF is 2 MB. Can it really go down to 100 KB?
Often, yes, if it is one or two scanned pages: most of those 2 MB are picture detail that a portal does not need. If the result looks too blurred, remove extra pages or switch on Black and white rather than going lower.
Is the result exactly 100 KB?
It is just under. The tool aims below 100,000 bytes, so the file passes whether the portal counts 1 KB as 1,000 or 1,024 bytes.
What if the tool says 100 KB cannot be reached?
It shows the smallest size it managed and lets you download it. Try Black and white, keep only the pages the portal asks for, or check whether the form accepts a larger file.