Background: Escalating healthcare expenditures highlight the need to identify modifiable predictors of the use and costs of healthcare and sickness benefit transfers. We conducted a prospective analysis on Danish data to determine the costs associated with flourishing as compared to the below threshold level of flourishing. Methods: We used data from a 2016 Danish survey of 3508 adults, which was linked to Danish register data. Flourishing was assessed with a validated psychological well-being scale. A two-part regression model was used to predict 2017 costs while adjusting for 2016 costs, demographic variables, and health status, including psychiatric morbidity and health behaviours. Costs are expressed in USD PPP. Results: Applying criteria from prior literature, the prevalence of flourishing in Denmark (measured in 2016) was 34.7%. Flourishing was associated with significantly lower healthcare costs ($-687.7, 95% CI = $-1295.0, $-80.4) and sickness benefit transfers ($-297.8, 95% CI = $-551.5, $-44.0) per person in 2017, as compared to the below threshold level of flourishing. Extrapolated to the Danish population (4.1 M people aged 16+ years), flourishing was associated with lower healthcare costs and sickness benefit transfers amounting to $-1.2bn (95% CI = $-2.3 bn, $-149.0 M). Conclusions: Flourishing is associated with considerably lower health-related government expenditure. Substantial reductions could potentially be achieved by increasing the number of people who are flourishing in the population.