Abstract Background In the German Federal Armed Forces (GFAF) workplace health promotion measures (WHPM) are implemented since 2015 to promote the health of military and civilian employees and thus improve the ability to defend state interests. Here the aim is to evaluate the social and health benefits associated with WHPM in relation to expenditures for WHPM. Methods Calculations are based on data from departmental reporting (full survey) on WHPM, the number of participants and days of incapacity for work (DIW). Mean indirect costs for the WHPM participation and DIW were calculated as 249.33 Euro per DIW. To assess the costs for the use of health care services and social and health benefits a longitudinal observational study (T0: 06-09/2022; T1: 06-09/2023) was conducted online and paper based. The survey invitation was addressed to 223.967 employees of the GFAF. Statistical analyses were performed using R software. Results In departments offering WHPM the chance of DIW is lower (-19%) compared to departments without WHPM offers and in case of DIW, the duration is shorter (-10%). In T0 23.568 (10.5%) and in T1 14.059 (6%) employees participated. 63.9% (T1: 3.070/4.805) reported positive effects of WHPM on their working ability and general health status (T1: 63.0% (3.013/4.782)). Of those participating in WHPM 81% (T0: 5.442/6.716) would recommend the GFAF as an employer. A number of 4.540 employees participated in both surveys, of which 2.249 participated in WHPM. The average costs per employee participating in WHPM compared to employees not participating are 0,4% higher (T0; T1: 3,5%) and thus almost equal. Conclusions Although WHPM need expenditures, the total costs per employee participating and not participating in WHPM are comparable. WHPM participants report better self-rated health status, higher working ability and commitment to the employer than non-participants. The chance of DIW is reduced in departments offering WHPM to its employees. *shared authorship Key messages • Although WHPM need expenditures, the total costs per employee participating and not participating in WHPM are comparable. • Employees participating in workplace health promotion measures report higher working ability and commitment to the employer.