Available balance is the amount of money currently present in a checking account or savings account. In other words, it refers to the amount of money that an account holder could spend or withdraw from the given account at the particular time. Each bank or checking account may have different methods of computing an available balance.
When money is deposited into a checking account or savings account, sometimes it immediately becomes available. If this is the case, when a new account is opened and $100 US Dollars (USD) is deposited into it, the available balance on the given account will be $100 USD. If another $100 is then deposited the next day, the available balance would be $200 USD, and so on. Generally, when cash money is deposited into a bank account, it is immediately added to the amount of money available in the account and thus the balance available changes immediately.
Money deposited is not always immediately available, however. For example, a check that is deposited may not be available until the funds clear from the bank from the check was issued. It can sometimes take several business days before the transaction is complete and money is considered to be deposited and available to the account holder. As such, the amount of money deposited into the account may be higher than the available balance.
Often, money is debited or removed from checking and savings accounts as well. This affects the available balance because when some money is spent, it reduces the remaining amount available for spending. Like deposits, sometimes withdrawals or debits can show up immediately and sometimes they are pending for several days before they show up. For example, an ATM withdrawal from a checking account may immediately reduce the balance available, while a purchase from a gas station may not reduce the balance available for a few days, until it is determined exactly how much was charged at the gas station and until the money is withdrawn from the bank account.
It is important to be aware of the balance available in a given account so no over-drafting of the account takes place. Over-drafting occurs when more money is taken from the account than is available within the account. In order to avoid over-drafting, it is a good idea to check the balance available before a purchase is made or a check written. Most banks will permit the balance to be checked online or via a telephone call to the bank; many banks will also send alerts telling customers what the balance available is in a given account.