What is JotForm?
JotForm is a free online form builder which helps you create online forms without writing a single line of code. No sign-up required.
At JotForm, we want to make sure that you’re getting the online form builder help that you need. Our friendly customer support team is available 24/7.
We believe that if one user has a question, there could be more users who may have the same question. This is why many of our support forum threads are public and available to be searched and viewed. If you’d like help immediately, feel free to search for a similar question, or submit your question or concern.
Sorry, but we do not have a calculation feature (for ordinary fields) yet. However, one of our able support team members might be able to provide you with custom script-based solution that requires modifying the form source codes and embedding them onto an external page.
I suggest you to take a shot - give us the name of the form you're working on and what exactly it is that you want it to do.