Use cases for Formula field

Total remaining estimate in unresolved issues	Example
Total time spent in closed issues	Example
Incurred cost	Pre-requisites Create another Formula field with the issue's Total time spent (See example above) Example field_1000 is the code of our Total time spent. Please check your ID and configure the expression with your ID
Remaining budget	Pre-requisites Create a Number field with the project Budget Create a Formula field with the project Incurred cost (See example above) Example field_1000 is the code of our Budget. Please check your ID and configure the expression with your ID field_2000 is the code of our Incurred cost. Please check your ID and configure the expression with your ID
Remaining time	Pre-requisites Create a Duration field with the project Original estimate Create another Formula field with the issue's Total time spent (See example above) Example field_1000 is the code of our Original estimate. Please check your ID and configure the expression with your ID field_2000 is the code of our Total time spent. Please check your ID and configure the expression with your ID
Number of issues	Example
Blocking bugs in QA	Example

When trying to know what is the ID of a Projectrak custom field ID, you just need to check de ID column. Please see the screenshot for reference.