**BVHall**I'm using the Configurable List widget to allow a user to add different booking dates for a room.

It simply displays the date to select, then the user clicks the + button to add another date and so on.

What I then need to do is to count the number of dates added and multiply that by another field (the cost of a room) to give a total cost.

What I cannot figure out is how to add up the number of dates entered by the user (ie if he has entered 5 different dates then I need to use the figure 5 to calculate the total cost).

How can I do this please?

*This is a re-post of a comment on Form Calculation - Math Function Reference*- JotForm Support
**BJoanna**Unfortunately it is not possible to perform calculations with dynamic fields, such as Configurable List or Infinite List widgets.

You can perform calculation with regular fields. You can also use fields such as Matrix field and Spreadsheet widget. However, this fields are not a dynamical and your users will not be able to add more fields.

How to Perform Form Calculation in the Matrix Field?

How to Perform Calculation in the Form?

Hope this will help. Let us know if you need further assistance.