Frequently Asked Questions

Question: Is it safe to convert PDF on

Answer: Yes, it's safe to convert PDF on All your files are treated as strictly confidential. All file transmissions are through HTTPS instead of HTTP. Your files will be saved to a directory with random 10 characters so only you can find it.

Your files are only temporarily stored on our servers for 1-2 hours, after that they will be automatically deleted by a scheduled program. You can see "Deletion Countdown" on conversion result page.


Question: How to convert an encrypted PDF?

Answer: The "PDF Password" input box is hidden by default, it will show automatically when you choose an encrypted PDF file. You need to enter PDF user password in the input box to continue conversion. The PDF encryption detection works on local by JavaScript instead of online by PHP, so it's very fast. You can also remove PDF password online first before convert it.


Question: What is DPI and what value should I enter?

Answer: DPI specifies the number of dots per inch. The more dots the higher the quality of the images (more sharpness and detail). 72dpi will output the same result as Adobe Acrobat when the zoom level is 100%. 300dpi is standard for printing, sometimes 150dpi is acceptable but never lower, you may go higher for some situations.

It's important, to begin with a high-quality image which means the highest resolution and image dimensions you can get. When it comes to source images, bigger is better, because you can go down in size, but not up, without losing quality.


Question: How many PDF pages will it convert?

Answer: It converts the first 50 pages of each PDF file. The number may change occasionally. Converting too many PDF pages may cause OOM (Out Of Memory) or overtime error. You need to split PDF to several PDF files first if your PDF files have hundreds of pages.


Question: How to reduce image file size?

Answer: There are two ways to reduce output image size.

1: Set a smaller DPI. The default DPI is 300 which will produce images with very high resolution. You can set a smaller DPI value to reduce image resolution.

2: Set a smaller JPG quality. Small quality means compressing for small size. The file size can be reduced up to 90% by changing image quality.


Question: How can I convert JPG back to PDF?

Answer: You can convert JPG back to PDF by our JPG to PDF online converter.

We strongly recommend our JPG to PDF Converter app for Android. JPG to PDF online converter is designed to work just like our JPG to PDF Converter app. They have the same PDF compression, protection and page size settings. Unlike the online converter, all functions in JPG to PDF Converter app can be used offline.