If you're having issues with a Calculation Field showing the incorrect calculation or not showing a calculation at all, check the following items to troubleshoot:
Field inputs are what you're referencing with the %f place holders in the calculation expression. Check to see that you a referencing the right Fields that you want to include in your calculation.
Blank Field Handling
If you are not seeing a calculation appear in your Field, check whether you have 'N/A' selected under Blank Field Handling. This will prevent your calculation from working until all Fields have been filled out, including Fields in a conditional Section/Sub-section that wasn't triggered. If you do have Fields in conditional sections, then it is recommended to select either 'Use 0' or 'Use 1' as a default option.
Actual Referenced Fields
If you are referencing Select, Multi-select, Radio or Checkbox Fields, then double check each of the referenced Fields to make sure there is a correct numeric value associated with each of your selections. Often times this is the root cause for miscalculations since Calculation Fields pull in the numeric values. By default a Select Text Value is assigned 1 as a numeric value. If you want this value to be something different be sure to change this in all of your Select Text Values.
Fields With Multiple Options Selected
For Multi-select or Checkbox Fields, the calculation will refer to the sum of all values for each option selected. For example, a field has three options and corresponding values -- Option 1 , Option 2 , and Option 3 . If Option 1 and Option 3 are selected for a record, the value  will be used as the referenced value for the calculation.