To better understand the tight post-pandemic labor market in the US, we decompose the decline in aggregate hours worked into the extensive (fewer people working) and the intensive margin changes (workers working fewer hours). Although the pre-existing trend of lower labor force participation especially by young men without a bachelor's degree accounts for some of the decline in aggregate hours, the intensive margin accounts for more than half of the decline between 2019 and 2022. The decline in hours among workers was larger for men than women. Among men, the decline was larger for those with a bachelor's degree than those with less education, for prime-age workers than older workers, and also for those who already worked long hours and had high earnings. Workers' hours reduction can explain why the labor market is even tighter than what is expected at the current levels of unemployment and labor force participation.