<p>This study critiques the reliance on pre-tax income to define the American middle class and proposes an alternative measure based on household expenditures, termed the Expenditure Middle Class (EMC). The EMC framework emphasizes consumption as a measure of economic well-being, consistent with neoclassical economic theory, which posits that utility is derived from consumption rather than income. Using data from the 2017–2019 Consumer Expenditure Survey, the EMC is compared to the Pew Research Center’s Income Middle Class (IMC) definition, which is based on pre-tax income. Results indicate that 62.8% of households qualify as middle class under the EMC, significantly higher than the 45.8% classified by the IMC. Trends from 2004 to 2021 show that the EMC middle class has grown slightly over time, contrasting with a decline in the IMC-defined middle-class size. Cohen’s Kappa indicates only moderate agreement between the EMC and IMC classifications. Subgroup analyses show that the EMC better captures economic well-being at the margins for discordant groups. These findings underscore that the middle class is a complex and fluid concept, and that alternative definitions can influence public perceptions of economic conditions, inequality, political behavior, and ultimately the formulation of economic policy.</p>