How do I format the calculation result?

I just tried your product.  I created a form and it works. I would like to know is there a way to format the calculation, such as percentage and to calculate the show a couple of decimal points out as well.

You could perform your calculation and then manually add the percentage sign (%), you may refer to this guide in order to get some help about how to perform calculations on your form: https://www.jotform.com/help/259-How-to-Perform-Form-Calculation-Using-a-Widget 

Regarding to add/change the decimal points, this can be changed on the calculation settings: 

Once there go to the options tab and select the number of decimals to be used in the result: 

I hope this helps.