PDF Medic OnlineCompress PDF to 20 KB
Make a PDF smaller than 20 KB for an upload form — the box below is already set.
Files never leave your device
How to Compress PDF to 20 KB
- Press Choose a PDF, or drop your file on the box above. It is read on your own device, not uploaded.
- Fit a size is already picked, and Must be under (KB) says 19. Leave it, or type the number your form gives.
- Press Compress PDF. The tool tries Best quality, Balanced, Small and Smallest in turn, and keeps the first one under 19 KB.
- Zoom in on the result and check that every word can still be read, then press Download.
What fits in 20 KB
20 KB is very little for a PDF. It holds typed text, or one simple scanned page. It does not hold a full page of small print scanned in colour, or a photo.
Here is what came out of our own test files at the strongest level, Smallest. Your file can land higher or lower, depending mostly on how much ink or detail is on each page.
- Typed text: ten pages of plain text with a standard font came to about 26 KB in total, so two or three such pages fit. This tool doesn’t shrink text, so a typed file stays about the size it is. Files that carry their own fonts start bigger.
- A short scanned letter, with a heading and about ten lines on an A4 page: about 16 KB. It fits.
- A scanned A4 page about half full of text: about 44 KB. It does not fit.
- A full A4 page of small print, scanned in colour: about 84 KB. It does not fit.
- A 3-page report with one photo per page, 2.6 MB to start with: 23 KB, still just over.
Is 20 KB the limit, or the minimum?
Read the rule on the form again. Some forms give a range, for example 20 KB to 300 KB. Then 20 KB is the smallest file they take, not the biggest, and a file squeezed under it may be refused. What you need is the upper number: use the Compress PDF to 300 KB page, or type that number in the box.
If your PDF is already inside the range, upload it as it is. This tool only makes files smaller, so it cannot lift a file that is under a minimum.
Why the box says 19, not 20
Many websites count 1 KB as 1,000 bytes, so their 20 KB is 20,000 bytes. This tool counts 1 KB as 1,024 bytes, so 20 here would be 20,480 bytes, which is a little too much for them. 19 here is 19,456 bytes, safely under both ways of counting. If your form’s limit is lower, type a number a little below it.
When it won’t go under 20 KB
If even Smallest is too big, you see “The smallest we could reach is …”. That file is smaller than your original and you can still download it, but it won’t pass a 20 KB limit. At this size, the fix is almost always to send less.
- Keep only the page the form asks for. Take it out with Split PDF, then compress that one page here.
- If you can scan again, scan only the paper itself, on a plain white background, without the table or shadows around it.
- If the form also accepts a picture, save the page with PDF to JPG and use Compress image to 20KB. The picture tool keeps lowering the number of pixels until the file fits; this PDF tool stops at its Smallest level.
- For what each level does to the pictures inside a PDF, see the main Compress PDF page.
Everything happens in your browser: your file is never uploaded to any server. You can check: once your file is open, turn on airplane mode — the tool still works.
Questions
Can a scanned A4 page fit in 20 KB?
Only if there is little on it. In our tests a short letter of about ten lines came to 16 KB, but a page half full of text needed about 44 KB. A page full of small print will not fit in 20 KB as a PDF.
Will my document still be readable at 20 KB?
To get this small, the tool usually ends at Smallest. That keeps at most 900 pixels on the long side of each picture, which is roughly 75 pixels per inch on an A4 page. Big text stays readable; small print, stamps and signatures can blur. Zoom in before you send it.
Why do I see “The smallest we could reach is …”?
Even the Smallest level left the file over 19 KB. Fewer pages, or a page with less on it, is the only way under. The file it made is still smaller than the original, so you can use it where a higher limit applies.
Can I type 20 instead of 19?
Yes, you can change the box. But 20 here means 20,480 bytes, which is over a limit of 20,000 bytes. Keep 19 unless you know the form counts 1 KB as 1,024 bytes.
My PDF is already under 20 KB. Should I compress it?
No. If it is under the limit, upload it as it is. Compressing a file this small changes little, because the tool leaves pictures under about 20 KB exactly as they are.
Is my file uploaded?
No. Compress PDF to 20 KB runs in your browser on your own device. The file is never sent to our server or anyone else. Once your file is open you can even turn on airplane mode.
Is it free?
Yes. No sign-up, no limits on how many files, and no watermark is added to your file.
Does it work on a phone?
Yes, in any modern browser on iPhone, Android, Mac, Windows or Linux. Very large files work best on a computer, because a phone browser has less memory.