This article presents a tractable and intuitive theory on the welfare effects of temporary tax cuts and subsidies, fiscal policies that I generically term "holidays." The Kaldor-Hicks efficiency effects are theoretically ambiguous, with competing pro-and anti-efficiency effects on newly incentivized versus time-shifted purchases. To rectify this ambiguity I derive expressions for the welfare effects that are consistent with constant elasticity assumptions and depend only upon readily and reliably observed information.To demonstrate the framework's broad applicability, I analyze two different policies: the 2009 Cash for Clunkers program and states' sales tax holidays. I estimate that both policies generated substantial deadweight loss. (JEL H21, H30, D91) * I received valuable comments from