Work time reduction via a four-day week finds improvements in workers’ well-being

Time spent on the job is a fundamental aspect of working conditions that influences many facets of individuals’ lives. We study how an organisation-wide four-day workweek intervention—with no reduction in pay—affects workers’ well-being. Organisations undergo pre-trial work reorganisation to improve efficiency and collaboration, followed by a 6-month trial. Analysis of pre- and post-trial data from 2,896 employees in 141 organisations shows improvements in burnout, job satisfaction, mental health, and physical health—a pattern not observed in 12 control companies. Both company-level and individual-level reductions in hours are correlated with well-being gains, with larger individual-level (though not company-level) reductions associated with greater improvements in well-being. Three key factors mediate the relationship: improved self-reported work ability, reduced sleep problems, and decreased fatigue. The results indicate that four-day workweeks with no pay reduction are an effective organizational intervention for enhancing workers’ well-being.