Form Calculations in Order Forms on 123FormBuilder

With 123FormBuilder, you can perform calculations on your web forms & surveys. Use form calculations to add mathematical operations between your fields on your online forms.

Form calculations offer a world of possibilities beyond simple data collection. Take an insurance company for example. By creating online insurance calculation forms, insurance agents can provide clients with immediate and accurate quotes tailored to their needs. This not only enhances the efficiency of the quoting process but also ensures transparency and client satisfaction. Let’s see how you can set up calculations on your online form.

Assign Values

First, you need to assign the values to your products/services. To do so, add a choice field (Single/Multiple choice or Dropdown field) and list the available choices.

Product list

Click the field to open its options in the right-side panel and select Price from the Payment & Calculations section.

Add a price

Next to each option type in their correspondent price.

Assign price

After saving the prices, this is what it would look like. By default, the prices are shown on the form, but you can disable that by toggling off Show prices on form.

If you need the user to type in a custom amount, add a Number field and assign the price “1”. By default, a field has no value assigned to it, meaning the input will be multiplied by zero.

number price

By assigning a value, the form will calculate input value X 1. (e.g. user types 123, the number field will calculate 123 X 1= 123  instead of 123 X 0= 0).

When you are using a Number (input) field, it also works as a quantity field. Assign the full price to the field (e.g. $150). If the user types 2, the calculation will be 2 X 150 = 300$.

Quantity field

Create formulas

To create mathematical operations on your form, add a Formula field. This field will show the total value in real-time.

Add a Formula field from the E-commerce & Calculations section. A calculator will appear where you can add operations between your form fields. Use the Add field button within the calculator to add your form fields. Once the field is selected, it will be automatically added to the formula. You can use your keyboard to add operators and values.

Formula field

Important Notes

  • You don’t need to enable payments on your form in order to use form calculations.
  • Formula fields are read-only.


  1. If I have a limited supply, such as 100 Widgets, how do I prevent more than 100 items from being sold? Where can I set the product limit?

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Here is a list of the most frequently asked questions. For more FAQs, please browse through the  FAQs page.

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