Autism spectrum disorder is a neuro-developmental disorder that affects communication and social skills in individuals. Screening and diagnosis of autism using conventional methods, such as interviews with parents or caregivers and observational assessments takes a long time. The accurate diagnosis of autism by physicians and healthcare professionals seems to be challenging. By analyzing data on autistic children, medical professionals can learn about autism screening assessment decision making. The present study aims to develop a parental autism screening tool termed the Indian Autism Grading Tool (IAGT) for early screening of autism. Data are collected using the Indian Autism Parental Questionnaire and assigned with grades. This dataset is employed to test five supervised machine learning models, which compare classification performance based on accuracy, precision and recall. The most effective model should be used to implement the autism screening application. MLR is known to be more robust and to support fewer data sets, so it can be employed for the implementation of ML-powered mobile applications. MLR achieves the overall accuracy of 97.85%, which equates to 0.72%, 2.37%, 0.84% and 1.54% better than SVM, DT, KNN and GNB respectively. The proposed tool is developed in both Tamil and English. The pilot study is conducted with 30 children and the predictability of the tool is compared with the clinician. Therefore, the tool consistently achieves the same level of accuracy as clinicians.