In automotive industries, leakage is one of the major problem reducing the efficiency in hydraulic and pneumatic system. The leakage in a device can be identified only during the physical test, once after the product is developed, leading to increased development time and cost. The leakage is purely based on the type of sealing element (O-rings) and sealing pressure. Since the sealing elements are hyperelastic and exhibit highly nonlinear behavior, there is no standard formulation available to predict the sealing pressure. It can be predicted using finite element analysis (FEA) in the design stage itself. One of the main inputs for the finite element analysis is the exact material parameter of the sealing element. This article aims at determining the sealing element material parameter using stress–strain data generated from uniaxial compression test and sealing pressure considering different hardness using finite element analysis. To generate the stress–strain data, compression force is applied on the test specimen at the rate of 12 mm/min and compressed up to 25% of its initial height with help of uniaxial compression test machine as per ASTM D 575. In this article, O-ring is considered as sealing element with hardness ranging from 40 IRHD to 90 IRHD.