Hello Axel,

You will need to use JavaScript to accomplish this. There are many JavaScript functions out on the web that you'd be able to modify to your needs. Basically you would create your JavaScript calculation function then call this function in the Client side event section under Advanced Field Options for both of the date fields.

Let me know if this makes sense and if you have any questions.

Thanks,

Ryan

Hi Axel,
Yes this is possible. You would be using javascript to do this. There is probably a function that gives the days between two dates function. One such place is at the following link: http://www.breakingpar.com/bkp/home...1000753DBF
This bit of javascript code may do well for you. Now to using it in a Dynamic Forms:

Now take that information and work with the following demo on datasprings like demo 20. It is a matter of using the 'client side events' in 'advanced field options' section and then using hidden fields to store values as needed to produce the result you are after.

For us to do this it is often a feature of our Premium Support area to supply answers of this kind. I will submit this example to management as we may also do a demo on it.