Create a Self-Calculating Total Field for Your Event Form

Written by Amy Jorgenson on April 7, 2014

Posted in Event Planning, Form Hacks

If you live in the U.S., this is an exciting time! We’ve officially entered “Spring” – although here in Indiana, it just snowed the other day … so I’m not buying into this spring stuff just yet.

With spring and the eventually nicer weather comes life: community service projects, races, community picnics, golf outings, fundraisers…etc. Whatever the event is, you can create a form with Formstack to conveniently coordinate the registration, ticketing, and signup process.

We have many tools that will streamline the process for you so that you can focus on the bigger picture. For one, we offer a feature called “Conditional Logic.” This feature is very helpful when you need to allow for multiple registrants/signups within a single form. You can show and hide fields/sections as needed to accommodate.

In my opinion, the best functionality for event forms is the fact that you can setup your price and donations fields once, create a calculation in your total field to sum them up, and integrate one of our payment processors to automatically handle the transaction. This means, you don’t have to worry about manually calculating up each registrant’s total due and processing it each time individually. Just think of the time you’ll save.

Let me show you how easy this is! You don’t even need to be good at math, just clicking! First, you’ll need to create fields to display your price(s). You can make it simple by using a multiple choice field – Checkbox, Select List, or Radio Button and adding the product values via the “use separate values” option and incorporate some read-only Number fields (or open-ended to collect donations). Or, you can use our handy Event Field – which allows you to display a picture of the product, set a price and description, and control inventory on the entire product and how many can be ordered per submission.


After you have all your product fields set, create a final Number field to sum them all up. You’ll just need to set up a basic formula using the field drop down to pull in all of the potential products and quantity fields, and we’ll do the math on the spot for you! If you aren’t familiar with this type of online calculation, you’ll have to click on each number and function rather than type it. Let me define a few functions to avoid confusion: the asterisk (*) is the multiplication symbol; the << symbol is backspace/delete, and the C is to clear the entire formula.

Your formula will look something like this:

[Product_1] * [Quantity_1] + [Product_2] * [Quantity_2] + [Product_3] * [Quantity_3]


Make sure you save when you are finished with your formula. That formula will automatically create a sum of all the values your end-users select on those fields in your form. If you change the values on the product fields, the formula will still work. However, if you delete or add a field, you’ll need to edit your formula to remove the deleted field or add the additional field to the calculation – it will not automatically update.

After you have your total field, you can map it to the Price/Amount field in your payment processor integration settings and begin taking payments! You can also create a dynamic Confirmation Email that will go out to your end-users after they complete the form showing their total paid – this can be used as a receipt/proof of purchase or you could get creative and make a ticket out of the dynamic data if necessary.

Have questions? Check out the support docs on our Knowledge Base or let our Support Team know by emailing us at!