How to compress a PDF to 150 KB
- Tap "Choose a PDF" or drop it onto the box. "Under a set size" and 150 KB are already chosen.
- Tap "Compress PDF".
- Check the new size, then download the PDF.
Good to know
The photos and scanned pages inside the PDF are made smaller step by step until the file is under 150 KB. Text, fonts and drawings are left exactly as they are.
If that still isn’t small enough, the pages are saved as images, at lower quality step by step, to reach 150 KB. The text then can’t be selected or searched, and we tell you when this has happened. Below a certain quality the pages would be hard to read, so the tool stops there: if the PDF still isn’t under 150 KB, you get the smallest copy it could make, and it says so.
We count 1 KB as 1,000 bytes and 1 MB as 1,000,000 bytes, so the file also fits forms that count in 1,024s.
Questions
Is 150 KB enough for a scanned page?
Usually, for one or two pages. Each scanned page is a photo, so it has to be compressed more the more pages there are. If the result is hard to read, try 200 or 300 KB if the form allows it.
Will the text still look sharp?
Yes, unless the pages had to be saved as images to reach the size. In that case the result says so, and you can try a bigger size instead.
Can I compress a password-protected PDF?
Remove the password first with our Unlock PDF tool (you need the password), then compress it here. A PDF that only blocks printing or copying needs Unlock PDF too, but no password.
How big a PDF can I add?
Any size: there is no limit of ours. The real limit is your device’s memory, so very large PDFs work best on a computer.
Is my PDF uploaded?
No. Your PDF is compressed by your browser on your device. Nothing is sent to us.
Page last reviewed 25 October 2026.