A trial balance is a list of accounts and their balances at a given time. Customarily, companies prepare a trial balance at the end of an accounting period. They list accounts in the order in which they appear in the ledger. Debit balances appear in the left column and credit balances in the right column.
The primary purpose of a trial balance is to prove (check) that the debits equal the credits after posting. The sum of the debit balances in the trial balance should equal the sum of the credit balances. If the debits and credits do not agree, the company can use the trial balance to uncover errors in journalizing and posting.
In addition, the trial balance is useful in preparing financial statements. A trial balance is a necessary checkpoint for uncovering certain types of errors. For example, if only the debit portion of a journal entry has been posted, the trial balance would bring this error to light.