Calculate the Total Number of Days Between Two Dates

Let’s create a Calculated Field that calculates the Total Number of Days Between Two Dates. 

Note: The App you create this Calculated Field in can vary based on your FreeAgent setup. We are using the Opportunities App for our example but a Contacts or Projects App works just as well.

To begin we will need the following fields in the Opportunity App:

• Date Created- A Date Field that contains the date the opportunity record was created.
• Date Closed- A Date Field that contains the date the opportunity record was marked as Closed.

See How to create a new form field for more. 

Begin by naming the Calculated Field and selecting what Section of the Opportunities App the Calculated Field will be displayed in (the choices will depend on your setup).

Next, click the Show Advanced Settings box and change the Calculated field to Yes. 

Now, select script Calculation Type. Enter the following code snippet into the Script window:

(function(opportunity){

 var StartDate = Date.parse(opportunity.Created);

 var EndDate = Date.parse(opportunity['Close Date']);

 var timeBetween = EndDate - StartDate;

 var days = timeBetween / (24 * 60 * 60 * 1000);

var justDays = parseInt(days);

 return justDays;

}(opportunity));

Your fields may have different names. Replace the bold field names in the code snippet with the names of your fields. 

Save the Calculated Field.

Add Validation

You could add validation for this calculation to return a '0' if the Close Date is not available. To do so, add an 'IF' statement, as shown in bold below.

(function(opportunity){

   var StartDate = Date.parse(opportunity.Created);

   var EndDate = Date.parse(opportunity['Close Date']);

      if(!EndDate){

          return 0;

      }

   var timeBetween = EndDate - StartDate;

   var days = timeBetween / (24 * 60 * 60 * 1000);

   var justDays = parseInt(days);

 return justDays;

}(opportunity));