The ATAR Estimator Tool is a practical online resource for students who want to understand their potential tertiary admission ranking. By entering academic information such as predicted marks or relevant scores, users can receive an estimated ATAR range that may help them prepare for university applications. The tool can be especially useful for comparing different academic scenarios. Students can change predicted results and observe how their estimated outcome may respond, giving them a clearer framework for setting study targets. This makes an ATAR estimator useful not only for prediction but also for academic planning. The estimated result should always be regarded as an indication rather than a guaranteed official ATAR. Actual rankings are determined by the relevant Australian admissions authority and may depend on jurisdiction-specific calculations, scaling, and other factors. Students should verify course prerequisites and admission requirements through official sources before making decisions. As an easy-to-access planning resource, an ATAR Estimator Tool can help students better understand their academic position and prepare for the transition from secondary education to university.