Also known as a gross balance, a book balance consists of the amount of funds that are on deposit in an account prior to making any type of adjustment to that balance. The term is also used to refer to the balance that is present in an account on the last day of the current banking period, or the end of the business month. From this perspective, the book balance can be viewed as the starting point for reconciling the account records held by the bank and the records maintained by the account holder.
Since the book balance is the gross balance of funds in the account before any checks are cleared or deposits posted, the figure may or may not accurately reflect how much money the account holder has to work with. In order to arrive at that figure, it is necessary to deduct any outstanding checks or other debits from that balance. Sometimes referred to as a net balance, this figure represents what is left after pending debits have cleared. By allowing for those pending debits, the account holder minimizes the risk of overdrawing the account, incurring penalties, and possibly having a check returned.
When it comes to pending deposits, it is usually not a good idea to add that amount to the book balance in order to determine how much of the account balance can be withdrawn or otherwise used. This is because of what is known as the float on the funds on deposit. Many banks have a policy of not applying the deposit to the account until the funds clear from the issuing bank. Depending on the nature of the deposit, this float period may take up to three business days. In the interim period, if the account holder writes a check that exceeds the current net balance, this could set off a chain reaction of returned checks or other disallowed debits, since the deposit is still pending, and is not actually posted to the account.
Knowing the book balance as of a specific date is important for several reasons. First, it makes it possible to reconcile the records of the bank with the records of the account holder. For businesses that must pay taxes on the outstanding balances within their cash accounts, knowing how much cash is actually present as of a certain day makes it much easier to calculate those taxes. In any situation, the book balance as of a specific date serves as a starting point to determine where discrepancies have occurred since, and make it possible to correct those accounting issues.