Create new calculated field

1. Let's add a Cost field which will be a calculated field - which will multiply "effort hours" by $100
2. Go to the App to "Add new field" and create field "Cost" being "Number" format and "Formula"
3. In the "Calculation" section put such a formula (JavaScript)

() => (entity.c_is_billable ? entity.total_real * 100 : 0);

4. Put this "Cost" field into the layout just under the "Is billable" checkbox

5. Publish the App and go to the timelog form to see how the result is seen by users:

6. If the user marks "is billable" checkbox - it will auto-calculate Cost field