Ergonomics is an important aspect of office space that employees use the most. Studies show the effect of ergonomics on health, comfort, and productivity, while subjective well-being aspect is underexplored. The study examines the relationship between flexibility in ergonomics, employee performance, and subjective well-being. Employees working in IT and ITES industries in India were part of the study. We collected data from 261 employees using convenience sampling. Partial Least Squares Structural Equation Modelling method using SMART PLS was used to analyse the data. Our study reconfirms that employee performance is a positive mediator and improves well-being. Contrary to the belief that ergonomics helps rectify posture and prevents the ill effects on health, our study says flexibility in ergonomics does not enable well-being directly. This study gives a base as to flexibility in ergonomics is not a direct indicator of well-being, while perception of productivity improves well-being.