A control account is a summary-level account in the general ledger. This account contains aggregated totals for transactions that are individually stored in subsidiary-level ledger accounts. Control accounts are most commonly used to summarize accounts receivable and accounts payable, since these areas contain a large volume of transactions, and so need to be separated into subsidiary ledgers, rather than cluttering up the general ledger with too much detailed information. The balance in a control account should match the total for the related subsidiary ledger. If the balance does not match, it is possible that a journal entry was made to the control account that was not also made in the subsidiary ledger.
The typical level of activity in a control account is on a daily basis. For example, all payables entered during one day will be aggregated from the subsidiary ledger and posted as a single summary-level number into the accounts payable control account. Posting into all control accounts must be completed before the books can be closed at the end of a reporting period; otherwise, transactions may be stranded in a subsidiary ledger.
If anyone wants to see detailed transactional information for accounts payable, they can review the detail located in the subsidiary ledger, since it is not located in the general ledger.
Control accounts are most commonly used by large organizations, since their transaction volume is very high. A small organization can typically store all of its transactions in the general ledger, and so does not need a subsidiary ledger that is linked to a control account.
A control account is also known as a controlling account.