Concrete is widely used as a construction material; due to its heterogeneous behavior, the service life of the structures becomes crucial so as to avoid the sudden brittle failures. Fracture in concrete is accompanied by emergence and evolution of an inelastic zone, fracture process zone (FPZ), around the crack tip. Inside this FPZ, many mechanisms occur: crack blunting, aggregate bridging, and microcracking, which prevent brittle failure. The softening of stress–strain curve in post-peak region and the size-effect phenomena is attributed due to the existence of this FPZ. As the size of FPZ influences the toughness of concrete—larger the FPZ, higher will be toughness; it becomes necessary to quantify the length and width of FPZ. Till now, the research was primarily focused on the length of fully developed FPZ. However, for better insight into the crack growth, an accurate prediction of FPZ size is necessary. Hence, precise quantification of width is also important. In this work, an attempt has been made to estimate the width of fracture process zone using v-displacement data of digital image correlation (DIC). The study aims to propose a methodology to find the FPZ width in plain concrete members. The maximum FPZ width for monotonic loading is estimated for geometrically similar beam samples. The proposed methodology has been verified against the existing literature on other non-contact techniques, and a good agreement has been found between them.