This study is designed to develop a mathematical model for measuring the stability of handheld application usage namely Stableness Measurement Model (SMM). This model outlined a series of formulas based on the total number of eleven stability measures (i.e. eight stability metrics and three stability attributes) which are identified as having associated and contributed towards measuring the stability of handheld application usage. This model is valuable as an alternative evaluation technique to be used for measuring and ensuring the stability of handheld application usage.