What’s the difference between Company Code and Controlling Area?
Company Code
It is the smallest organizational unit in FINANCIAL ACCOUNTING (FI) for which a complete set of accounts can be created. It is the central organizational unit of external accounting within the SAP system. Normally, a company code is created for each company (legal entity). It is a mandatory and pre-requisite that at least one company code must be defined before implementing the Financial Accounting component. All business transactions relevant for Financial Accounting are entered, saved and evaluated at company code level. Therefore, it is at company code level wherein a complete set of financial statements (Balance Sheet, Income Statement, Statement of Cash Flows) can be created.
Controlling Area
Controlling Area in SAP is an organization that represents a closed system used for cost accounting purposes. It is an organizational unit in the Controlling (Management Accounting) separate and has different functions with that of the Company Code. One ore more Company Codes can be assigned to a Controlling Area.
SAP SIMPLE Docs 