Implimenting Total Modifier

I am trying to add an option to accept donations as a percent of the total purchase. How would I use conditions or calculations to modify the total when a donation option is selected by the user?

Hi,

You could add a field asking if they would like to make a donation.  Then associate the "No" option with a calculation value of 0 and the yes option with a calculation value of your percentage:

Then setup your calculation to take your total and multiply it your percentage, then add that number to your total:

Here is my test form so you can see the setup working in your form:

http://support.jotform.com/form/51195892713967

http://www.jotform.com/help/42-How-to-clone-an-existing-form-from-a-URL

It is currently adding 3% but you can adjust this value to whatever you would like.

If you have any further questions or need any help getting this setup in your form, let us know and we will be happy to help.

That was a huge help but I modified the form slightly to make it look cleaner. I am still having issues getting the total to change so the user can see the total prior to submission. Thank you for taking your time to help me out. Rather than having 2 separate fields, I just posed the question with radio buttons to simplify the form and the process for myself as well.