With CaptainForm you can perform calculations on your web forms & surveys. Use form calculations to add mathematical operations between your form fields on your online forms.
To create calculations on your form, add an input field with numericplus validation. This will return the value of your calculation formula. You can also add calculations between the Time and Date fields. The operation between two Time fields, for example, will return the value in number of minutes, while the one between Date fields will return the value in number of days. Go to the Settings → Payments section of your form and select the field in the dropdown list below Assign Values or Formulas to Fields.
Select Formulas in Add Values or Formulas. A calculator will appear below where you can add operations between your form fields (Date, Time or numeric input fields). Use the dropdown list within the calculator to add your form fields. Once the field is selected, it will be automatically added in the formula. You can use your keyboard to add operators and values. In the end, press Save Changes on top.
Note: You don’t need to enable payments on your form in order to use form calculations. Form fields that have been assigned as formulas cannot be overwritten by form users.