In micro-machining applications, cutting parameters should be selected carefully to avoid premature tool breakage. The cutting forces can be estimated by using available theoretical models. However, according to the characteristics of the tool holder and material the error could be significant and a time consuming fine-tuning could be required. In this paper, a well-known theoretical model was compared with experimental data, and a Cutting Force Variation Estimator (CFVE) package was developed to estimate the cutting force variation. The package could be easily trained based on simple cutting force data and could therefore, be used to estimate the cutting force variation in a wide range of tools, feed rates, and cutting speeds.