What is Expense?

An expense is any outflow of money to pay for a good, service, or financial obligation. Household expenses divide into three tiers for budgeting purposes: fixed obligations (rent, mortgage, car payment, insurance premiums, minimum debt payments), variable necessities (groceries, utilities, fuel, prescriptions), and discretionary spending (restaurants, entertainment, travel, hobbies, subscriptions).

The Bureau of Labor Statistics tracks national spending patterns through the Consumer Expenditure Survey. In recent years, housing has consistently been the largest single category, consuming roughly 33% of average household spending, followed by transportation (16%) and food (12%). These percentages shift significantly by income level—lower-income households spend a higher share on necessities, while higher-income households allocate more to discretionary categories and savings.

From a tax perspective, most personal living expenses are not deductible. However, certain categories receive preferential treatment: mortgage interest and property taxes (subject to limits), student loan interest (up to $2,500 annually), medical expenses exceeding 7.5% of AGI, and charitable contributions. The IRS distinguishes between personal expenses and business expenses; the latter are deductible against business income if they are ordinary and necessary under IRC Section 162.