A debit to an expense account is a bookkeeping entry that records a decrease in the balance of an asset, liability or equity account. When recording a debit to an expense account, funds are transferred from one account to another and the amount of the transaction is recorded as a negative number. For example, if a business incurs a $100 expense, it will debit the expense account for $100 and credit cash for $100. Unlike a credit entry, which decreases expenses and increases assets, liabilities or equity, a debit to an expense will increase an expense and decrease either cash or liabilities.