Expansive soils are one of the problematic soils faced worldwide and pose a serious challenge for civil engineers. they are a potential natural hazard that can cause extensive damage to structures if not treated adequately. expansive soils are those which experiences a great change in volume (swelling and shrinkage) with a change in water content. the phenomenon of swelling in expansive soils depends on the minerals present in the soil. expansive soil molecules exist in layers or as plates. when water is added to the soil, they occupy the place in between the soil layers and hence causing the increase in the volume of the expansive soils. such soils swell in the presence of water and shrink when the water dries out. this change in volume can exert enough force on a building or other structure to cause damage, it also poses a significant hazard to foundations. free swell index (fsi) is the increase in the volume of a soil, without any external constraints, on submergence in water. it is one of the major parameters while calculating swelling in expansive soil but it is a very time-consuming process. it takes 24 hours to calculate the fsi value of a given soil sample(as per is-2720-part-40-1970). during this time the sample should remain undisturbed. the objective of this project is to find the fsi of soil in less time using more sophisticated and accurate methods like image processing. this is the latest method of calculating fsi value and nothing like this is ever done before.