Difference between two days

Version 1

    Hello Everybody,

     

    I need your help in a specific formula. In Excel, i used this way =(TODAY()-DATE(2013/1/1))/30 and the result should be 14,57. How Can i do the same calculation in Tableau to use this result as a another argument in a formula ?

     

    Today i create a calculated field like this ZN(sum([D2_QUANT]))/14.57 but this number changes each month, i need to fix this to be automatically.

     

    And my idea was ZN(sum([D2_QUANT])/today()-date(2013/1/1))/30 and me result should be .

     

    Hope anyone can save me.

     

    Regards,

    Renato Rocha