How to add number of checks in a checkbox field and save into a numeric field?

I want to add the number of boxes someone has checked in a particular field and put that in a hidden numeric field.  What is the easiest way to do that?

You can assign a value to each option of the checkbox and then create a condition that will copy that value and put in another field.

Please check this demo form: https://form.jotform.com/71174865477973. You can clone it if you like to. Here's a guide on how I created that demo form:

1. Insert a Multiple Choice field and Short Entry Text field.

2. Please assign a calculation value for each option in your Multiple Choice. Just select the field and then click the "Properties" button. Go to the "Surveying" tab and put a "1" value in each line under the Calculation Values. Here's a guide: How-to-Assign-Calculation-Value.

3. After that, create an "Update/Calculate Field" condition. The condition states that if the "Fruits (Checkbox)" is filled, the value will be copied to the "How many fruits? (Textbox)" field. Here's a related guide: Conditional-Logic-Inserts-Text-Calculation-Into-A-Field.

Here's the result:

Hope that helps. Let us know if you have any questions. Thank you.